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Five Signs That Your Car Has a Bad Heater Core

Wrench Wench has been in love with automotive mechanics for decades. She loves sharing advice with fellow DIY mechs and curious cats.

You might experience only a few of these symptoms, or you might experience all of them at once. A lot of this depends on your vehicle, its age, and its health at the time when your heater core goes bad.

You might be wondering what the heck a heater core is, what it does, and how it can affect your vehicle. These are all great questions, and we’re going to get you some quick and easy answers so that you can get your car fixed ASAP.

Signs That Your Car Has a Bad Heater Core

  1. It's foggy in your car.
  2. Your car smells odd.
  3. Your car is devouring coolant.
  4. You have a chilly passenger compartment.
  5. Your car's cabin is cold, but its engine is hot.

More Questions Covered in This Article

  • What is a heater core?
  • What does a heater core do?
  • Where is the heater core located?
  • How do you change a heater core?
  • Can you drive with a bad heater core?
  • Can a bad heater core cause overheating?
  • How do I stop my heater core from leaking?
  • How can you tell if you have a blown head gasket?

This article will also explore the most common questions sent in by fellow readers in the "troubleshooting" section towards the bottom. If you have more questions as you read, make sure you scroll all the way to the end (another reader has likely had the same question).

1. It's Foggy in Your Car.

Is it foggy in here? The most common tipoff to a problem with a heater core is when the inside of your car suddenly fogs up for no reason. And, when I say "fogs up," I'm not talking about a little mist on the edge of the windshield, I'm saying every window is covered with moist, warm condensation.

What may have happened is that your heater core blew while you were driving, after the engine warmed up. The warm coolant leaking into the cabin of the vehicle caused fog because that coolant was previously sitting inside a warm and temperature-regulated coolant system, and now it's evaporating into steam as it hits the cooler air inside your car.

2. Your Car Smells Odd.

Do you smell melons? Whether or not the car got all foggy when the heater core broke, an unmistakable sign of a leaking heater is a fruity, sickly-sweet smell inside the car. This is the smell of your radiator fluid and definitely a sign that coolant is leaking into your car.

You might also smell this lovely smell around the outside of your car, which means it's time to look underneath your vehicle and see how much of that coolant has spilled out onto the ground.

3. Your Car Is Devouring Coolant.

Is your car rather thirsty? If you find your car, truck, or van has suddenly developed a voracious appetite for coolant, and you cannot figure out where it's all going, you may well be looking at a blown heater core. Sadly, if the leak is hard to find, the reason may be that the coolant has been leaking into your cabin when the system is cold, and instead of making fog it's creating a puddle. The first place I usually check to confirm a bad heater core is the passenger-side floor. If it is soaking wet, and so are any forgotten shoes or fast-food bags lying around down there, then I know to suspect the heater core.

4. You Have a Chilly Passenger Compartment.

Brrr! It's cold in here! A chilly passenger compartment is not always a sign of a faulty heater core. It may indicate that your blower motor or another component of your heater has gone bad (cheer up, it may be a component that’s less tedious to fix than the heater core). Though, if you're seeing one of the other signs in addition to a lack of heat that's a pretty good indicator that the heater core itself has a problem.

When a hole or puncture develops in your heater core, all that warm air may escape too quickly to reach you at the other end of the heater ducts. Depending on the size of the puncture, you might feel mildly warm, lukewarm, or absolutely freezing air coming from your heater.

5. Your Car's Cabin Is Cold, but Its Engine Is Hot.

Do you have a cold cabin and a hot engine? If you find that your vehicle has overheated, or continues to overheat, you'll want to check on the health of your heater core for sure. Bear in mind though, that many other parts of the car could be involved in the overheating. If your heater stops putting out heat, and your engine seems warm, investigate whether there is a coolant leak elsewhere, or some other issue with your car.

Overheating is very serious for your car. All sorts of major components of your car will wear and break down in record speed when they get too hot. If your car overheats, investigate the problem and get it fixed ASAP. If the temperature gauge goes up into the danger zone, don’t drive it; tow it. You don't have to heed my words, but I can guarantee you'll learn a hard lesson if you don't.

What Is a Heater Core?

It’s part of the car’s cooling system. It looks exactly like the mini-me version of your radiator, and is, in fact, a small radiator itself, with a grid of little tubes and a waffled appearance from the fins that disperse the heat. Your heater core allows your heater and defroster to function.

What Does a Heater Core Do?

Your heater core circulates coolant through the little tubes; the coolant comes in through one heater hose and out the other, radiating heat into your cabin so you don’t freeze on those cold winter mornings. It's also responsible for allowing your defroster to function properly, and it's linked into the air conditioning system, which is organized around similar principles.

Where Is the Heater Core Located?

Your heater core is usually behind your dashboard, under the center or the passenger side. It will have some sort of casing or housing and is usually buried behind almost every other component of the dashboard.

How Do You Change a Heater Core?

This job is way easier to describe than it is to perform. Often, a DIY'er will check out a Chilton's Manual or other auto guide and say, "No problem! I can change a heater core!"

I'm all for this kind of enthusiasm; it's how I myself got into changing heater cores. Though, let me forewarn you that it is a very tedious task, and once you know how to do it, all your friends and family will want you to change theirs too!

With that warning out of the way, I'm only going to give you a very basic guide for most cars and trucks from 1958 to 2010. For the details for your particular vehicle, you'll need to do your own digging.

Steps Required to Change Your Heater Core

  1. Disconnect the battery.
  2. Remove the steering wheel from the vehicle.
  3. Remove any outer doors or casings from things like the fuse box, speakers. and kick panels.
  4. Remove the glove box, radio, speakers, and any accessories.
  5. Remove any gauges (be careful if you have a speedometer cable back there!).
  6. Detach and remove your heater and air conditioner controls.
  7. Unbolt and remove the dashboard.
  8. Do not disconnect your air conditioning unless it's absolutely necessary and only if you have the proper means to dispose of the Freon. Do not just let it leak into the air. It is bad for the ozone layer and is toxic, especially to people with heart conditions.
  9. Disconnect the two heater hoses from the engine compartment.
  10. Move any air ducts or other components away from the heater core housing.
  11. Remove the heater core housing and set it on a table. Remove any screws or fasteners to gain access to the heater core.
  12. Take the old core out and put a new one in!

Note: To install your heater core, just follow these instructions in reverse. If anything got broken on the way out, please make sure to replace it on the way in.

Caution: As with most DIY tasks, you take on this one along with all the risks involved. These instructions are very basic and meant for a person who is already very mechanically inclined. If you don't have appropriate tools, safety knowledge, and a strong mechanical aptitude, you'll want to seriously consider taking your vehicle to a garage to be fixed by a professional.

Can You Drive With a Bad Heater Core?

A heater core often goes bad due to leaking. As the heater core uses engine coolant to generate heat, a leaking heater core will reduce the amount of coolant in the cooling system. Low coolant will cause an engine to run at a higher temperature, which can result in extensive engine damage.

Can a Bad Heater Core Cause Overheating?

Leaks are the #1 reason a vehicle begins to overheat. Leaks in hoses, the radiator, water pump, thermostat housing, heater core, head gasket, freeze plugs and a few other things can all lead to problems with the vehicle's cooling system. A small leak can quickly turn in to an expensive repair and a serious headache. Often times, the problem could relate to a blown gasket

How Do I Stop My Heater Core From Leaking?

If it is only a small leak in the heater core, most would recommend simply sealing that leak and leaving your heater core in place. You can do this simply by adding some gasket sealer to your vehicle's radiator when your vehicle is cold.

How Can You Tell if You Have a Blown Head Gasket?

There are some makes or models of cars that have a reputation for blowing head gaskets. One such vehicle has such a bad reputation for head gasket problems there is a group of owners trying to get the manufacturer to have a recall on them. If you happen to own one of these vehicles, don’t worry it does not mean that you have a bad car or that you are going to spend lots of money.

How To Tell if a Head Gasket Is Blown:

  • Coolant leaking externally from below the exhaust manifold.
  • White smoke from the exhaust pipe.
  • Bubbles in the radiator or coolant overflow tank.
  • Overheating engine.
  • White milky oil.
  • Fouled spark plugs.
  • Low cooling system integrity.

Question: Is It Possible to Have a Broken Heater Core and Not Exhibit Each of the Signs?

I own a 2005 Honda Civic. Lately, my a/c has been on and off. It runs Lukewarm and, as I gain speed, it gets colder. My passenger side floor has been thoroughly soaked, but not recently. However, I have not had any problems with coolant being low. No overheating. I'm certainly not a mechanic. I get in and drive. If it needs gas I fill it up. If it needs oil, I get it changed. That about sums it up. Is it possible to have a broken heater core and not exhibit each of the signs?

Answer: Yes! It's Definitely Possible

There are plenty of times when heater cores will go bottom up, and only barely exhibit one or two symptoms. In 90% of cases, you're going to clearly experience at least two or three signs that give away the culprit.

In your particular situation, especially without any loss of coolant, while I wouldn't rule out a bad heater core, I would look first towards your air conditioning unit. While it's not unusual for an aging vehicle to take a little time to blow out crisp and cold air, if your a/c is on the fritz, it could also be the culprit soaking your passenger side floor. Alternatively, you could also have a leak in the seals around your door, windshield or firewall—all of which could be soaking the floor as well.

Question: Still Smelling Coolant, Is This Normal?

Just bought a 2008 Chevy equinox. That same day I could smell antifreeze while the heat was running, so I took it right back and they said bad heater core. I got it back today, heat works great! However, I can still smell a very slight scent of antifreeze. Not like before, and it even seems to lessen as I drive, but when I restart it, I smell it again (slightly). Could this just be normal after having one fixed? Maybe there's a residue in the vents or something? I'm hoping it just goes away after a day or so. What's your opinion?

Answer: Yes... and No...

Yes, it's not unusual to smell a bit of residual coolant drying up in the system.

That being said, it's not normal for this smell to persist for more than a few days of driving. So, in greater detail to your individual plight, since you are describing a chronic type persistence in this smell, I would urge you to take your chevy back to the mechanic and have them check for any small leaks in your coolant system. While it could just be some residual coolant, it's more likely that there is a small leak somewhere that wasn't caught originally, or that occurred after your last heater core was replaced. It's not unheard of for this to happen, especially if your vehicle overheated or if there was any serious pressure in the coolant system when the heater core went bad.

Question: How Much Does Repair of the Heater Core Cost?

I am positive I have a heater core problem. Ironically, it started the day I got my car back from getting a fuel pump relay repaired. After paying a lot for the fuel pump relay, how much does repair of the heater core cost?

Answer: The Ballpark Price of Heater Core Replacement

This is a difficult question to answer, because it depends on what country and/or state you live in, what type of mechanic you see, and what type of vehicle you drive.

That being said, I can offer a ballpark idea of what I might charge and what common prices are found in my area (Seattle, Wa).

For me, a heater core is often a large job, not because it's difficult, but because in nearly all vehicles, the heater core is behind the dashboard. So, unless I have direct experience with a particular year, make, and model that I've performed this on, my initial assumption is that it will take no less than eight hours to disassemble the dashboard, retrieve and replace the heater core, and then reassemble the dash around it again. This is a general time estimate, including most newer cars that usually have lots of delicate electrical elements, clips and knucklebangers. As a mobile mechanic, my usual going labor rate was $60 an hour. So a general estimate for a heater core would be around $480.

Now, shops in the area, who often have more specialized tools, lifts, and predictable work environments, can often get the job done in half the time. That said, because they are running a business, their shop rates are going to be higher—$90 to $150 average. So for a 4-6 hour job in a shop, you're looking at a minimum of $360 to $600, plus the price of their preferred manufacturers heater core.

Question: Where's That Leak Coming From?

I own a 96 chevy corsica four cylinder. Two days ago, on my way back from work, I smelled a very sweet humid icky smell (coolant) inside my car. I kept driving only to see that white smoke started coming from my vents and my car started rapidly overheating. I pulled over to let the car cool about six times on the way home. When I got home, I looked under the hood and saw that all of my coolant was gone, after just getting it filled two weeks earlier. I asked around and everyone kept telling me that it was my heater core. Everyone also kept telling me to look for the missing coolant on my passenger side floor. It's still dry. I jacked up my car to find a leak and poured a gallon of water into the coolant compartment to do just that and I quickly jumped under the car. What I found was that all of the water was pouring out thru a one inch pipe connected to absolutely nothing right underneath the heater core. However, there was no leakage from the actual core itself. I was wondering if you could tell me if that is still a heater core problem or something else before I start tearing my dash apart? Please and thank you.

Answer: Pipes to Nowhere...

Okay, I first have to thank you for sharing this complication. To tell you the truth, without being able to stick my head under your hood, it's a little bit difficult to narrow down what you're seeing precisely. That being said, from your information, I would suggest that it's likely that your disconnected "pipe" either used to be connected to your heater core as a part of the inlet hose.

Your heater core is a really basic set up. You have your main radiator in the front of the car and two hoses (it's not often that they are pipes, but it's not unheard of), an inlet and an outlet, that connect to the corresponding pipes attached to the heater core. These pipes will often protrude from the fire wall, which is where I suspect you're seeing this "pipe to nowhere."

Question: What Are the Symptoms Before the Heater Core Goes Bad?

My mom's car just got repaired. Either the radiator or the fan kept turning off. Now, every time we turn the heater on in the car, it will be warm, but I can smell something sweet, like syrup, almost. I was worried about it, but someone told me that it wasn't the heater core because it won't give you any warning before it causes damage. They said that the mechanics probably just accidentally spilled some antifreeze. I really don't know what to think.

Answer: Bye Bye Heater Core...

I have to say, while I'm sure they meant well, it's sure naughty of your friends to assume that a+b always equals c, when it comes to cars. I'm no master mechanic, but out of everything I've learned, and that all other mechanics I know have learned, it's that vehicles don't always act the way they are supposed to. In fact, I'd imagine that 90% of professional repairs could be handled by any old monkey with a wrench, if it weren't for the fact that cars and trucks get old. Sometimes they are straight up text book, sometimes they do something completely bizarre and unexplainable, and you find out that it's something super easy and right in front of your face.

When it comes to heater cores, it's extremely common for them to leak out into your passenger compartment, because they are usually right up underneath the dashboard inside your car. Though the leak could be from somewhere else, such as the inlet or outlet hoses, where they would spill out onto the ground. If that happened, you wouldn't have your passenger floor soaked.

The same thing could be said about heater core's just "dying" without any warning. That is very common, though it's not because there are not any signs before hand, it's because most of us are too busy driving to notice the signs unless they stick out. So, smelling coolant, could definitely be a sign that your heater core has a slow leak and may need to be replaced soon. That being said, it doesn't mean that it is your heater core. If it were me, I would use a coolant leak checking tool, or take it to a shop and have them use one. In the first day or two after having a radiator changed, it would be expected to smell a little bit of drying coolant, but a chronic smell every time you turn the heater on, shows there is definitely something worth checking out; before something just dies on you without warning.

Question: Foggy Windows

I have an '01 Malibu. I've replaced the thermostat and the heater core, thinking that would stop my car windows from fogging up, but even after those repairs, my windows are still fogging up. What's wrong?

Answer: Check Things Out

Without knowing more, my initial suggestion would be to have your new heater core and thermostat checked out. In this instance, it would more likely be a faulty thermostat than a faulty heater core, though you won't know until you have them checked.

That being said, before going too much further, I would also check out the seals around your windows. It could be something as simple as a seal leak that is allowing moisture into your car and preventing them from completely defrosting.

Question: What if My Heater Core Connection Is Broken?

If my heater core connection is broken, what can I do to remedy the situation? Do I just need to buy a new one? Can I retrieve a broken connector?

Answer: Call Up an Auto Parts Store and Get a New One

You should be able to call up any auto parts store and get a new one. Last I checked, they're fairly inexpensive. As far as retrieving the broken connector, without more details I'm mostly just guessing as to how much of the quick connector broke off. So, with those guesses, here are some YT videos that I hope will help. If they don't, it'd be best to take the car in to a pro for this one.

Question: What If the Windows Aren't Fogging Up, but I'm Still Getting Coolant on the Floor Boards?

My windows aren't foggy, but I'm still smelling coolant. What if the windows aren't fogging up, but I'm still getting coolant on the floor boards? Thoughts?

Answer: It's Still Worth Investigating

If the windows aren't fogging up, but you're still getting coolant on the floor boards, it's still worth investigating further. That would seem more like a leaky heater hose, but could also be a small hole in your heater core, which would be better to have repaired now, before things get worse.

Most Common Car Problems

Area of ConcernDescription


Of the near-5,000 reported faults since March 2015, expensive gearbox repairs top the list, accounting for 8.4 per cent of all problems.


As cars are loaded with more tech than ever, electrical gripes are the second biggest problem, adding up to 8.2 per cent of all Warrantywise claims.


As mileage racks up, slipping or burnt out clutches can become common, contributing to 7.8 per cent of claims.


One of the priciest faults your vehicle can develop is with the turbocharger. This is increasingly frequent, making up 4.7 per cent of Warrantywise claims.


Having fully functioning brakes is the most vital feature of your car, so it’s disappointing to see faults developing on so many used examples (4.7 per cent).


The traditional alternator could be phased out with the advent of hybrids and electric cars, but it’s an issue in used models, with a failure rate of 4.3 per cent.

Cylinder head gasket

White smoke and coolant leaks are symptoms of a cylinder head gasket failure; 3.1 per cent of cases involved vital gasket repairs over the last year.

Air-con condenser

Air-con is a necessity for those odd hot days. New condensers accounted for 3.1 per cent of problems.

EGR valve

Exhaust gas recirculation valves were at the heart of the recent emissions scandal. Data shows faulty parts made up 2.9 per cent of claims.

Window motor/regulator

Gone are the days of winding your windows down by hand. But even modern motors can burn out; fixes were required in 2.2 per cent of cases.

Share Your Experience, or Ask More Questions

I love to hear old heater core job stories. They can be epic battles, depending on what kind of vehicle we're talking about. If you leave me a question or a story in the comments below, please tell me the year, make, and model of your vehicle.

You're looking for answers, and I'm looking to give you answers! So, you ask them in the comment section below, and I will answer them as quickly and as accurately as I can. Please keep in mind that the more details you can provide about your car and your problem, the better quality advice I can give you.

Also, if you're question is not answered in this article, please check my other articles, as I might just have created a whole new hub with your question in mind!

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

Questions & Answers

Question: My blower motor and AC seem to be working good and I recently changed the thermostat on my 2012 Jeep Liberty, yet it's still overheating. What should I try next?

Answer: Without more information, I would suggest your next step is to check your heater hose inlet and outlet hoses, which come out of the top and rear of your motor, and then into the firewall. If those hoses aren't pinched or broken anywhere, I would recommend replacing your heater core.

Question: Would a leaking heater core cause the driver's side floorboard to be wet?

Answer: Yes. Many vehicles have heater cores that are more centrally placed, meaning it can leak on either side. Though it could also be a leak from your firewall (a grommet or anything similar). Check to see if you're low on coolant and then check to be sure the vents below your windshield are clear and clean.

Question: I have a heater problem, it won’t fully blow heat and doesn’t put out a lot of power. What could be wrong?

Answer: I would first check to be sure you have coolant in your radiator. If it's low or out, you won't get any warm air & that shows you have a coolant leak. If your coolant levels are fine, then replace your blower motor.

Question: My heater was really blowing hot air and then I heard a whine underneath the car, I shut my heater off and it quit. What would cause my car to whine and quit when I turned off my heater?

Answer: I would check your water pump or the blower motor.

Question: I have a 2003 honda civic. Water has been appearing on the driver's side floorboard. Could this still be a bad heater core? I have good heat, though I am losing coolant. Everything I've read talked about the passenger's floorboard, could it still be the heater core if it's leaking on the driver's side floor?

Answer: In most vehicles, the heater core is located over the passenger side; hence the common signs of bad heater cores say to check the passenger floor board. Though many heater cores are placed more towards the center, especially in front-wheel drive vehicles like yours; hence, they can leak on either side. Considering that you are losing coolant/water, it is highly likely that it is your heater core which is leaking.

There are a few reasons you could still be getting heat, though I would focus on your coolant leak first.

Question: I have changed the water pump and thermostat on my 2006 Chevy Silverado 2500hd with a 6.0, and now there is coolant pouring out of the a/c condenser drain tube, but it stopped as soon as I bypassed the heater core. Any ideas what is wrong and what I need to do to repair it?

Answer: Sounds like your heater core is faulty; replace it & it sold resolve the leak from your condenser tube.

© 2014 Wrench Wench


Kevin from Washington on January 23, 2019:

I have a 1963 Beetle, similar to the opening picture. I have noticed that the windows are steamed up, it smells odd, and the passenger compartment is cold. I can't find the coolant reservoir to check the level. I also searched everywhere for the heater core with no luck.

; )

DavidM01 on December 31, 2018:

Heater Core on a 2000 Jeep Grand Cherokee has my hair on fire!! I flushed the heater core and the water flows fine and is clean! But despite both lines going to firewall being hot, the Heater Core stays cold !! No heat comes towards the cabin side!! Blend Door area is now cut open and they both work. Actuator also works and operates the blend doors! Is there a FUSE / Switch / Vacuum line somewhere that is supposed to trip the Heater Core!? Thanks for all your hints.

Baker Baker TDMaker on December 27, 2018:

Have a 2008 Pontiac Torrent. Heater did not work well last year. This year, no heat. Before I could get it in, car overheated. Garage added Coolant - not sure they really investigated anything- and seemed to mostly fix issue for 2 weeks. For 2 weeks I had heat, but only when car was moving, and no over-heating issues. Then slipped right back and now have no heat and car overheats. other symptoms:

1. Gurgling noise behind dash occasionally

2. gets foggy on inside of car when heat doesn't work

3. Reservoir is full but mechanic added coolant to radiator directly? and it mostly resolved issue for 2 weeks

Wrench Wench (author) from Seattle on December 07, 2018:

Yes, usually it will, and if it is fogging the window, that's a confirmation that you're heater core andor heater hoses need to be changed.

That all being said, if the windows aren't fogging up but you're still getting coolant on the floor boards, it's still worth investigating further. That would seem more like a leaky heater hose, but could also be a small hole in your heater core, which would be better to have repaired now before things get worse. Specially on something as sweet as a 75 Cadi ;)

Wrench Wench (author) from Seattle on December 07, 2018:

Hi there Paul! I believe the "nipple" you're referring to, is called a "Heater Hose Quick Connect"

You should be able to call up any auto parts store and get a new one. Last I checked they're fairly inexpensive.

As far as retrieving the broken connector, without more details I'm mostly just guessing as to how much of the quick connector broke off..So with those guesses, here are some YT videos that I hope will help. If they don't, it'd be best to take the car in to a pro for this one.



There doesn't seem to be much more available. I'll have to write up a hub to provide more detail ;)

Till then, please be careful and don't be shy about coming back with my questions!

Wrench Wench (author) from Seattle on December 07, 2018:

Absolutely! And without experience performing other kinds of tasks, it's easy to not realize that Heater Cores require different things in different vehicles. My Jeep Wrangler was one that someone with intermediate experience could've figured out, but in the corvettes I used to work on, it took half a day just to get access to the Heater Core without damaging anything.

RuthyAnn7377 on December 01, 2018:

I have a dodge nitro and the engine was rebuilt two years ago for not having any heat and it was the head gasket out the car runs beautiful and i have heat but when you sit at a stop light or just idiling it turns cooler then when you drive again its hot and heats up the cabin..it doesnt overheat runs beautifully could this be a clogged line from the heater core or the heater core itself? no dashboard lights as well

cris on November 27, 2018:

I bought a 05 forester off a craigslister, and with it..the farm! had no idea, in addition to other issues i'd be looking at this, -- tear into the heater core. But there it is (wherever t h at is). Fog was the first clue and (i) thought it was just a lack of air-flow; but couldn't get it to clear by any means - some suggested the problem resolves by killing on the a/c (to remove moisture through the a/c system) - so, I rolled down the windows to get a natural de-fog effect. And nothing doing! Then I saw 'smoke' coming out the vent by my window, and went, "Aha! i know what t h at is!" So now that's what i'm looking at. Anyway, for one of my heater core stories, --it was a cold and blustery night (up here in the mountains), and my '74 Pinto wasn't doing good..well, the windshield was all fogged; and you could smell that sickly, sweet smell of anti-freeze..the green kind. Yeh. And then, it was dripping the stuff on my boots (yeh). UYeh, so I knew I had a problem. And the rest of the story is I got a new core and installed it. But was it painful!!! down there, there is zero room to reach the incoming hoses and re-fasten the new unit..period. That was a hard job. But I did it. Now the brakes failed, and while it set, for about 6 years, it's missing 2 cylinders out from the fire-wall, oh whale!

Steve Reiner on November 18, 2018:

Just pulled the heater core out of an 04 Ford f150xlt 4.6l. Heater core blowing antifreeze on inside of cab windows. Probably have done 20 or 40 heater core changes in different vehicles. This thing is one that you should have help with, as you need to drop the metal dash support also. You need to move things around in the engine compartment because there are a number of studs that protrude through fire wall. Not for the novice, don't even go there, especially if the vehicle is sitting outside, those doors have to stay open, so if it's bad weather either get it inside or wait until it's decent out. This truck, takes time and probably one of the more time consuming of any I've ever done. It's not something for your first heater core change. If you want to go for it, good luck with this one.

Paul L. on November 15, 2018:

The small hose nipple that goes from the engine to the heater core area of my 2003 Lincoln Towncar has broke off. Half still attached to engine other half in the hose. Does the nipple screw into the engine? what is best way to install new nipple? Thanks so much for your help.

Chris on November 09, 2018:

2005 Jeep Liberty, 208,000 miles. No heat comes out of vents and A/C would only blow on settings 3 and 4. resistor fixed the blower issue and flushed the heater core and radiator. Mechanic said it was extremely gunked up and took several flushes to clean them both out. No heat again today after working for a few weeks. Where to now?

Carlos on October 22, 2018:

My 2007 dodge ram 1500 heats up and leaks water or antifreeze onto the passenger side floor when i turn on the heater it also leaks antifreeze thru the ac drain pipe underneath the truck

Chauntai on September 23, 2018:

Hi i have a 2005 toyota matrix xrs and the heat blows hot on drivers side and cold on the passengers side what could this be do i need to flush my heater vore

Beverly carbaugh on August 06, 2018:

I have question. My passenger side is dry but my drivers side floor is wet. What could be the reasoning for this

Amanda from Atl GA on June 30, 2018:

I drive a 99 f150, one owner (my dad) before me and it has 139,000 miles. It's never missed ANY scheduled maintenance and was driven by my OCD, can fix absolutely anything (no joke), biomedical engineer father. The only actual repair it's ever had, other than normal maintenance, is a fuel pump. I tell you all this for you to know what kind of condition the vehicle I'm talking about is in.

Anyway, I noticed that the passenger side floor board was wet. It took a second for me to realize I definitely had not spilled anything, so I began to investigate. When I pulled up the floor mat, there was no puddle, but it was soaking wet. It has not overheated. If it's losing coolant it's not enough for me to notice. No fog. I have been searching for fruit that had been left in there to no avail, but the smell was not the same as any coolant I've ever smelled, but it did smell like rotten fruit. My father will fix my car for me, but not unless I can diagnose it. Could this be the heater core? If not, do you have any idea what other issues would cause a sopping wet passenger side floorboard? I do know it is Not bad window or door seals. Any advice would be greatly appreciated.

Thank you for your time

Sandra on June 07, 2018:

I have a question I have a Jeep Liberty Sport 2003 6-cylinder and my knock sensor needs to be replaced my check engine light came on I bought the part I just need to find someone to do the work and also my AC worked great and three days ago I went to turn it on and it stopped working it only pushes out cold air when I'm driving and I have to be going pretty fast do you know what that could be

Harry Fricker on May 08, 2018:

With my car AC blowing cold and in the on position, will my heater core still fog windows? Fluid leakage on passenger floor is barely noticeable. Anti freeze in the system is never low. The auto is a 1975 Cadillac Fleetwood brougham

Wrench Wench (author) from Seattle on April 05, 2018:

Hi Alex! Thanks for reaching out. I hope you're able to keep track of these comments, as I'll do my best to help ya out as well as I can from the other side of this computer, lol.

So, I ran your jeep conundrum past a few seasoned friends, just to be sure, and we all agree that the first thing you should check for, is AIR BUBBLES in your coolant system. It's a very common problem that can cause all sorts of unbelievable chaos.

I'll have to write a hub about that later, cause I've had some similar situations to yours (I had a 1993 wrangler with coolant system challenges), and it always drove me nuts to find that after replacing nearly everything, it ended up being just a bubble in the system that keep causing it to overheat for no "apparent" reason.

You can easily see if this is the problem by letting the Cherokee run with the radiator cap off. Stand and watch, or have a friend stand and watch for bubbles to come up. They'll likely be many small bubbles, but do be careful, as there can be some big ones too, and they can splash hot coolant around. Watch for the bubbles to start to dissipate, then replace the cap and let the jeep run for 20 mins. If it doesn't overheat, take it for a very SHORT drive up the street and back. Park it and take the radiator cap back off and let it run again, while watching for bubbles. If after 5 mins, you don't see any bubbles, replace the cap and try going for a longer drive. At that point, you shouldn't experience any more overheating, and have successfully burbed your jeep.

If that doesn't work, you'll want to check your passenger side floor board for water/coolant, as you said you haven't done your heater core yet, and that could still be a source of problems.

The other option off the top of my head, is the Thermostat Sensor -- which is usually replaced at the same time as the thermostat. If you haven't replaced it, do it now, as it's usually less than 10 bucks, and could also be your culprit.

Outside of that, try getting another new thermostat, as there is the semi-rare occasion that you'll get a dud thermostat from the parts store. Thankfully, they will usually just replace it straight across.

Anyways, I hope all goes well! Please come back and let us know what ends up working for ya, or if ya have any other questions =)

Alex Krauss on April 03, 2018:

I am here in complete desperation. I have been working on my 1998 Jeep Cherokee Classic for a solid week trying to diagnose the problem. It is the 4.0 Inline 6 motor. The vehicle was dead 3-4 weeks ago and had sat for a year because of a blown head. It has been overheating. I have changed the thermostat, water outlet housing, water pump, radiator and all hoses. It has a brand new head gasket as well. We have not done the freeze plugs, fuses, overflow jug and heater core. It starts and runs for about 10-15 minutes before it starts to try and overheat. It stops right above 210 on the temperature gauge for a little bit, but very soon buries the needle to 260 and the "Check Gauges" light comes on. It then begins to smoke from the engine bay. It seems as if no matter what I change, it continues to overheat. When driving it will do everything i just said in the same motion, but also begins to make a loud "Tacking" sound. The sound is not coming from the engine itself. I have not been able to locate this sound. I read on google that it could just be the bearings in the pulleys getting to hot? I really need some help if anyone has ideas.

Wrench Wench (author) from Seattle on March 14, 2018:

Hi Phil! I've been in your position before. If you, or anyone else who finds themselves with a similar challenge, can clean up your passenger side and then keep a close eye on it for the next 2 to 7 days, you'll have your answer. If your heater core is bad, you will find more green coolant on your passenger floor board. Even just a small trickle is a possitive indicator. If you find nothing at the end of the week, it's much more likely that something leaked in during the car wash. Possibly some turtle wax.

Phil on March 05, 2018:

I took my 2010 Mercedes c300 thru car wash yesterday. I noticed the floor mat on passenger side wet. Blower on AC wouldn’t come on either. Do I have heater core leak? There was green water in cabin air filter also. I thought it was car wash but being green and coolant green and in filter not sure now. Only noticed after car wash but did change temp form heat to cool during that time. Your thoughts ??

Tim on February 17, 2018:

04 Chrysler Concorde 3.5 initial issue...overheating the leak at water pump. Now what I did. Changed water pump, timing belt and idler pulley. Also changed thermostat with failsafe stat, and temp sensor. No leak now but still overheating. Tried bleeding several different ways that was suggested. Took to dealer and they said bad radiator. Changed that then failsafe stat locked in open. No overheating achieved but no heat. Took to a friend with lift and changed thermostat to a standard one plus crank and cam sensor then had a no start issue. Changed ECU and had it flashed now starts and runs but overheats. Instrument panel has slight interior fog but not windows nor floor. What’s the issue??? Help

Rowan Snyders on February 15, 2018:

I own a ford Focus 1.8si 2010 Model, there is a stinky coolant smell coming from the vents. Everyone I spoke to is telling me that it is my heater radiator that needs to be replaced. However now my water and coolant is disapperaring as well. I was recommended that if I dont want replace the heater radiator as it is a big job, I can bypass it by connecting the the two pipes that goes to the water radiator. But I see a bigger problem, I am loosing water when I drive in traffic, or let me say when I get home and park... I have no Idea where this water is leaking from?

Wrench Wench (author) from Seattle on February 05, 2018:

Hi Sue! Thank you so much for your question! I'll try to provide you with a short answer here until I get an article written to answer your question with greater detail and precision.

For now, the direct answer is: Yes, you can flush your heater core at anytime, though doing so might not show you if your heater core has failed.

The first thing I would do, which should be in the article, is to check the passenger and driver side floorboards under the carpet. If they are wet and you have no known leaks in the wind shield, than it is likely your heater core leaking, especially if the "water" on or under the carpet smells sweet.

Another thing you can do, is get a large deep pan under your vehicle, then one at a time, remove each heater hose from the car. With the other side still connected, have a friend or spouse get in the car and turn over the engine, then prepare to get sprayed, cause if the inlet and outlet hoses both work fine, you should get wet. If either of them have no pressure or suction (one of each), then your heater core has failed or gotten clogged internally.

Doing it this way will save you having to completely flush and refill your coolant system with expensive coolant. Though if you have the time and don't mind the cost, you can just drain the coolant & then stick an active garden hose inside the radiator neck & let it run while you remove each heater hose & see that they are both working properly.

Like I said though, getting positive results doesn't necessarily mean the heater core is fine, especially if it's sprung a leak in one of the coils.

Anyways, please let me know if you decide to continue pursuing a flush and if I can help you more right now while I work on an article just for this automotive challenge =)

Best of luck!

Sue Nichols on February 03, 2018:

Can i flush out my heater core to see if it has gone bad and if so how do i do that

wpoore on January 09, 2018:

have a old 1997 dodge intrepid-3.3 motor--windshield fogs up with defroster on--car does not heat up like it should.

no wet floor---also the window does not fog up all the time

could this be just a bad thermostat?----she only has 240,000 miles on her----ha--and the cowl vent screen is gone---the plastic just got to brittle and broke away so that area is all exposed----

Rick Spring on December 21, 2017:

Can the heater core be damaged during the rebuild of a transmission. We have a Dodge Journey 2009 and they just rebuilt the transmission and now the heater core needs replacing. They're claiming they have nothing to do with each other.

Sean C. on December 17, 2017:

My 87 Toyota pickup was exhibiting signs of a blocked heater core, so I bypassed it to finish my cross country trip home. After the head gasket finally sprung a leak,I had the hg replaced,and the mechanic reconnected the core,saying it seemed fine.

Fast forward 7 months,and this past august,the core seemed to block again, so I once again bypassed it.

Yesterday,the truck once again overheated (with the core bypassed)...could the bypass of the heater core cause more rapid consumption of coolant..?

debbigettman@yahoo.com on December 11, 2017:

2008 impala does not warm up inside but temperature guage is normal no leaks or smells..once you start driving it gets warm..blows hot-air.when idling blows cold..had radiator flushed still same symptoms

Raymond on December 03, 2017:

I flush my heater core but nothing came out flush it for a 1 hour both ways does it mean that I need a new one

Steve Bennich on September 03, 2017:

What would cause a heater core and water pump to both leak at the same time? I have a 99' Cadillac Escalade. Not long after having the intake manifold gasket replaced, I started experiencing leaking from the water pump , then from the heater core ( fogging of windows inside, especially front windshield, passenger side floor board wet, etc).

Ron D. on July 21, 2017:

I have a 03 Chevy Malibu and going on 4 years now I have smelled Coolant when I start my car and run my heater or aircon, that goes, away in a short while. However, I see no loss of coolant between changes, nor do I see any on my carpet or steam fogging up my window. My heat gets plenty hot and my aircon blows very cold. How can my heater-core be leaking all this time without a total blowout?

Dan on June 12, 2017:

Ok. I have a 2003 Envoy XL. I haven't noticed any of the typical signs of heater core issues. I noticed antifreeze coming out just in front of my driver door. I looked everywhere and saw no leaks. Checked water pump, resiorvior, anywhere I could think of. There's a set of lines going to the rear A/C running through there but that looks fine. The antifreeze appears to be draining down the chasis. I don't want to take everything apart just to check the heater core and it not be. Any ideas?

Isaiah Cope on May 24, 2017:

Stephanie Robuste: Hi, Im Isaiah. I have an 01 s10 pickup truck and my windows fog up also. My AC just went out in August and it was my compressor. My heater core just went out last night on my way home from school. I attend the Automotive Technology Center in Troutman Nc. I have seen this before a bunch and I believe I can diagnose this for you. I think that you have a vent that wont open or close causing it to either to stay open all the time or closed all the time. If your ac is bad it may cause fog cause the defroster isnt working. If nothing works, you may have a leak somewhere, you can tell if you smell coolant inside the car. I suggest using Rain x wipes and Rain x widow cleaner with the no fog stuff. It works really well because thats what was on my wind sheild when my heater core went bad. Maybe the car is really humid on the inside for some reason. I just want you to know that i am not ASE certified yet but i am working on it. I just enjoy helping others who need help. I hope it works. Good luck.

johnny on May 17, 2017:

hey, heater core OR thermostat, 1998 4 door sedan base model cavalier, 2.2 l engine - overheating, coolant disappearing, within 15 minutes engine redlining, can sometimes hear gurgling noise coming from somewhere inside or under dash(?), when heat is turned off. sometimes temperature fluctuating on gauge, other times right up on bust! heater core was never change. Need replacement??

Anthony on May 03, 2017:

I own a 2011 Chevy Aveo LT. I recently had the radiator replaced due to a leaky hose and crack but a few weeks later I noticed the cabin smelling like a minty sweet aroma and its only when the car isn't moving.

I checked for leaks, wet/soaked floor boards, overheating, etc and so far nothing. It drives just fine also, so any help you can give me will be greatly appreciated.

James Salley on March 02, 2017:

I have a 2011 bmw 328i I was told heater core was clogg up but heat comes out good on driver side cold air on passenger side. Dose not lose antifreeze no smell dose not leak on floor dose not steen up windows how can it be heater core ???

Alfred on January 30, 2017:

I have a 05 Ford Mustang v6. I have had leaks in the passenger seat, freezing on cold days.. heater doesn't get hot, coolant leaks out every other week... so I'm pretty sure it's the heater core. In need of a step by step to completing this job..

Teresa on January 28, 2017:

I have a 98 chevy cavilier the heater core went out on it so we bypassed it for now but now my car will not start could the heater core stop it from starting up it will turn over just not start

Linda on January 20, 2017:

I have a 2008 jeep patriot,my heat works fine and my temperature gauge is normal,but this morning it looked like maybe steam coming from under my hood,and my coolant level is fine,which does that mean?

martin on January 15, 2017:

Is it possible to skip heater core??

mary duane on January 14, 2017:

2006 dodge charger, heater works great but powdery smell comes out of every heat option except the one that blows heat on top and bottom.

FrankB on January 13, 2017:

Car was running hot with no heat.After new water pump and thermostat same resut.Could heater core cause overheating.Its almost as if theres no circulation

Kay on January 09, 2017:

I have a 1989 Chevy caprice and it's giving to much gas if I'm driving and tries to stop it wouldn't I'll have to put it in park and turn it off .. what can be the problem??? Please

Debbie on January 08, 2017:

Had a new heater core last winter had no heat coming from defrosted or upper heat vents. Was not hot air only lukewarm today I started my jeep liberty 2012 and heard a loud cracking noise and then there was no heat coming out of top passenger heat vent all others are working and air is still very hot. Can an actuator do that? Can a heater core block just one vent?

Michele on December 15, 2016:

Took out Ac pump cuz it didn't work now I have no heat.Any idea

Trevor on December 11, 2016:

Thanks for your expertise. I have an 05 Tahoe, first I'm not seeing none of the signs except my front heater is not working. My fan works great, as does my rear heat, but my front heat worked sporadically and now has since stopped working. Before I pour money into getting my heater core changed, could it be something else? Thank you

Jason on November 27, 2016:

Got a 2011 Nissan Frontier with 64,000 miles on it. The truck will blow hot air running down the road with the heater going, but when I come to a complete stop it will start blowing cool air while the heater is still on. I don't feel that it is a blown heater core, I haven't seen any leaks, don't have any foggy windows when I turn the heater on, nor do I have any odors coming from my truck. I think it's just a clogged system. Can anyone clarify

David on November 23, 2016:

I have a El Camino 85 heater core is in engine compartment how do I replace

Brandon Myers on October 31, 2016:

I have a 1976 ford granada and I noticed I have a hosee coming for the inside of the car threw the firewall. Is that the reason I could not be getting head inside the car

Elvis mcgilvray on October 01, 2016:

On 2000 taurus it has a bypass line off. Top htr core line with it clamped off could it affair with trans.lines overheting.

Charlotte on September 03, 2016:

I'd like to know how long or should you drive a car IF you know or think it's a heater core you need.. I DO have a sweet white smoke from My vents.

Kris on August 19, 2016:

I own a 1995 Toyota T100 and my problem Started as leak by my evaporator core then a few days pass and I'm sitting a red light and I notice that my AC is blowing a thick fog out my two center vents I'm almost positive now that it's the heater core

Jay Avila on August 18, 2016:

If one of the hoses going into the heater core leaks, does that mean the core is going bad or just a simple leak. Want to avoid all that work of replacing the core if i don't have to.

mike on August 14, 2016:

have 2004 cavilier water coming out of lower heater if bad heater core would smell antifreezze drain works what elso could it be?

dominic on June 10, 2016:

Eyes burning nose stopped up all the time and I always smell like something burning in .y freightliner coming threw vents

ydroza on June 05, 2016:

I had to get my radiator replaced in Jan 2016 as my Jeep Wrangler '07 started guzzling coolant. $4000 later, when I got my jeep back I noticed a strong smell of coolant inside the car and the windshield misting over.

Called the mechanics once again and was advised that told the there was a leak from the water pump. Nothing to do with the previous issue of radiator leaking. Paid another $700.

A week later called the mechanics again because the windshield was still misting over and there was smell of sickly sweet coolant inside the jeep. They put it under stress test and told me that there was nothing wrong.

Now 5 months later having driven with the sickly sweet smell of coolant all through I feel that the mechanics have been shoddy but I'm not technical enough to have an argument with them and I am loath to part with another 1000$.

Just wanted to check if this would have been an issue that the mechanics should have discovered when they initially repaired my vehicle or can they keep telling me that it's not related and I have to pay again?

Pam on April 20, 2016:

2002 jeep liberty sport, flushed heater, new radiated, new thermostat, cabin heat only heats to 60 to 80. Why isn't it heating properly?

Alexander Silvius from Portland, Oregon on April 04, 2016:

That kind of confirmed it for me, thanks! I also appreciate the round about price guess you offered, it gives me something to work with as I add up the expenses for my beautiful beast. I love my old wagon and she has been reliable all the years I have had her. It needs a lot of maintenance, but I think it's still cheaper than a car payment. I probably spend an average of 2000 a year on her, sometimes less if I put things off.

Mary on April 03, 2016:

If my radiator is broken and I need a new heater core...which one should I fix first?

Wrench Wench (author) from Seattle on March 22, 2016:

@Robert Collins, yes there are certainly other things it could be, and your smart to check them all before shelling out the big bucks for a new heater core, especially since you are getting water in the back of the car and not the front, which is not where any of your heater core components are located and not likely to be the heater core at all. With the info you've given me, I would first check:

-The seal around the sunroof - you can easily check this by having someone sit inside the car while someone else sprays a hose on top of the car. Just watch and wait. If there's a leak, you'll see it.

-The sunroof latch (make sure it latches firmly)

- The Sunroof Drain Tube - In your model of car, these drains "should" be underneath the rear plastic sill plates or "runners" that are screwed into the frame of the car. You'll see them when the door is open. Unscrew them and gently remove the runners, then look for a little plastic tube. It will probably be white or gray. The tube "should" run off into an outlet hole with or without a "port". These annoying little tubes tend to get clogged and then they backup and start draining inside the car. You would think the owners manual or the car makers would warn people, but they don't. If you can find it, push some air through them with an air compressor. Even a little air compressor might only run you around $40 bucks, which is way better than $1500 and you'll need it to clean the tubes again if this is your current problem.

You could also try doing what the guy in this video does, though you might need to remove any "ports" or filters they've placed on the end of the drain tube, in order to get the crud out of there.

If you still haven't found the leak, check:

-The seals around all doors (Use the hose again)

-The welds underneath the headliner (the fabric on the ceiling of the car) closest to the doors (Use the hose again)

-The floorboards under the front seats. You'll have to pull up the carpet to check the floor boards.

-The seals around the rear windshield (get the hose again)

If you don't find the culprit from any of these places, a great way to check and see if it really is your heater core, is to drain all the coolant from your system, then put a hose into the radiator and let it run. Let it over fill and keep going. Get into the car and wait to see if you get water inside the car. Again, this almost always happens in the front, usually on the passenger side floor, but if your car is just bizarre, you'll see water coming in from running the hose in there.

Good luck and let me know when you find the source of the leak!

Robert Collins on March 16, 2016:

Completely confused. I have a 2012 Mazda 3. We have a couple signs that there might be a bad heater core,but the water we have is in the back only. there is zero water in the front passenger floorboard. we don't have the sweet smell, but when we turn on the air it takes awhile if at all for the AC to work. At first we thought that maybe there was a leak from the sunroof as the water only appeared after a rain or car wash. Not I just don't know. I don,t want to dish out $1,500.00 for a heater core and then find that's not the problem. Do you have any comments that the sun roof may be leaking or can this water problem be from some other source?

Bigbremac@yahoo.com on February 14, 2016:

Heater core has been bypassed in the past in a 87 Lincoln Continental. Just bought the vehicle in New England where it is very cold and I was told the vehicle had only been driven in the warm weather before. I am wondering some safe ways to test the current heater core that's in place such as trying to run water through it but running the risk of getting water on electronics in the dash area. I am also seeking a safe way to open the bypass connected to the radiator hoses to test and hopefully connect the hoses to the heater core and test after connection. Sorry ahead of time if this is too much. Included my email in case I don't see this.

kevin on February 11, 2016:

I have a 2000 f250 and no heat I have changed everything and now I am looking at the heater core it is hot on the top and bottom but in the little fan that blows cold air right through

Pam on February 03, 2016:

I live in Arizona. I haven't used the heater in years.

pam on February 03, 2016:

It's ok to bypass it, right?

Wrench Wench (author) from Seattle on January 21, 2016:

Bypassing the heater core is an interesting choice. I hope you don't intend on driving your car in the winter, lol

Rob Hampton from Port Richey, Florida on January 20, 2016:

I think I am just going to bypass the heater core.

craftybegonia from Southwestern, United States on January 19, 2016:

This is very useful information, especially for those of us who are really ignorant when it comes to auto mechanics. Thanks for sharing!

Wrench Wench (author) from Seattle on January 17, 2016:

Elaine, thank for your question. First, I would check or have your Blower Motor checked. Usually if it's a heater core, you'll still air, it just won't warm up. If you're getting at all, my first thought would the blower motor.

Elaine on January 16, 2016:

My heater was working fine earlier and i went out but no heat or air coming through the vents i have a 94 suzuki sidekick, any suggestions

Wrench Wench (author) from Seattle on January 12, 2016:

I haven't had a moment to look up that model, but in many vehicles, the heater core is more towards the center of the car, instead of being right above the passenger side floor. When they're more in the center, there's greater potential for coolant to spill onto the drivers side floor. I remember the first truck I went to work on that had the exact same problem; coolant soaking onto the drivers side floor. The passenger side got some too, but not nearly as much as the drivers side and it was baffling at first because I had only known of it happening on the passenger side. Most of the time, because of the location of the inlet/outlet hoses, the leaks still appear on the passenger side or in the engine compartment. Though the only thing I could think of was that had to be the heater core, as there really was no other reason for coolant to be coming into the cab of the truck. The rest of the coolant system is all in the engine compartment.

So I tore out the dash, removed the heater core and ran a crap ton of water through it and found it had been leaking through one of the bottom welds that had separated over time.

The only way to really double check this theory, is to drain your radiator and then stick a hose in it and let it fill up and over run. Then go inside your trailblazer and stick your hand up behind the center console (Where the radio and such is) and wait to see if you feel any water coming through. It might squirt a little or a lot, or you might just notice the carpet getting wetter. If the leak is small, it could take a while to notice anything or you might not notice anything at all. Doesn't mean it's not the heater core, but that's the only way I can think of without specialty tools, to check the core before removing it.

As far as any of this having to do with the stereo your buddy installed, it's highly unlikely it had anything to do with your heater core leak unless your friend is uniquely talented and somehow decided to stick a stray screw deep into your center console and somehow got it right into the coils of the core. Though that was be some AMAZING talent, lol

william on January 12, 2016:

Question ; 2002 trailblazer has antifreeze on DRIVER SIDE floor. Is it more than likely my heater core? I noticed it after my buddy installed a new stereo???

Jason on November 11, 2015:

I feel sorry for anyone who has to do this crappy task. After varifying that the ac/heater controls were all working and the acuator door was functioning and the blower motor was working I was left with no option but to swap the heater core in my 03 sonoma 4.3L step side.

My only benifit is that I build custom cars so I have a full shop and heated garage ,but for the average DIY guy with a handful of tools you use for oil changes and plug changes I would not recommend this as a home project. I have seen many people come into my garage with there ride on a tow truck because they can't get the dash back in or worse yet they didn't disconnect the battery and managed to set off an airbag ripped the wiring harness ect ect.

If you can't afford to take this to a shop where most likely the bill is going to be close to over a $1000 look in your local classifieds for someone who can do the job for you that has the skill set who can do the job. There is always guys like me out there who are willing to do these nasty jobs for a decent price and like myself most are gearheads who hold a class A licience in automotive repair.

Samantha on November 09, 2015:

My husband (who is a diesel tech) replaced a corroded hose coming from my heater core that had a pin hole in it. We thought that might fix the problem of no heat in my van but there's still no heat. The windows don't fog up, my floor is not wet, and I don't smell anything sweet in the van but when I turn on the heat there is a loud whistle like sound that won't go away for a while when it's turned on. Could this be the blower motor going out? If we replace that will I have heat in my van again?? it's getting too cold out to have my babies in my van with no heat.

Margaret on November 08, 2015:

We have a Ford Focus 08 every time you turn on the heater or air conditioner it smells like rubber then it kinda goes away, any idea what it could be.

Jason. lucidspider69@yahoo on October 12, 2015:

So my coolant has a leak and i could fill the coolant get pressure and drive it without overheating. However i tried bars stop leak in it. And something happened when i drove ot last. The engine over heater and smke started pouring out of my heat vents and hood. What is wrong with it is it a heater core. Head gasket. Or?... please let me know what u rhink and rhe smoke smelt bitter

Terry on September 16, 2015:

I have a 2001 chevy silverado 1500 4.8 liter...I'm thinking my heater core has a hole in it for sure. The passenger floorboard is soaked n smells like coolant and when I park the truck and turn the engine off it comes out pretty good from underneath as well. This doesn't look like a fun job no matter the make or model!! Any tips to make it easier along the way??

herndog58 on July 23, 2015:

Where do I find the answers to these comments?

Specifically to teddy 7 months ago?

boscho on July 20, 2015:

my damn ford 150 is a bitch. my window fog n it runs hot. i go to crank it up it dont even stsrt now

jenn on July 12, 2015:

I have a 94 ford flair side and I smell a sweet small inside of my truck and my windows will fog up what does that mean

Nay Valitio from Orlando, FL on June 21, 2015:

Seen this thread & wanted to add, plus ask question. Per my Dodge Ram 1998 Chilton book it says if steam on windows fogging occurs but it's cool check hoses for being clogged (clean them). Took truck to 4 mechanics all said just change the core, no one wanted to even listen to me or believe me even when showing them the book. Passenger floor not wet, no smell, just fogging up, still had heat and good heat. Only thing was turning it on sometimes the windows would get like a shower and the steam, fog would come out like a fire was going on my truck. This was pretty bad considering had moved to GA right before it snowed 2013 and GA shut itself down. Well I personally replaced the compressor A/C (easier than I thought) and nice cold air but 1st day in use after recharging and evacuate done it soaked the floor on passenger side. Now I still have heat, still get cold air checked coolant but not low. Prior to compressor it was sucking coolant but floor was not wet, never saw coolant on ground, but a wet substance certainly not green. I added Best Line product to radiator (not even 1/4 of bottle) prior to leaving GA back to FL and no signs of fluid being low. Checked noticed passenger side not wet. Question: if hoses are clogged and it's not circulating like it's supposed to wouldn't that keep the radiator level consistent but near heater core low which would mean it's trying to pull or suck fluid through but there is nothing there? And can I perform a hose flush myself? Since I can't get a mechanic to do it I'll perform myself. Thank you.

linda on June 15, 2015:

I have a 2007 ford taurus do a heater core stop a air condition from working

Sharon on June 07, 2015:

I have water dripping from under my dash except it's not hot it's very cold and there's no fog or anything like you described,do you have any idea what might be wrong please help

theresa on May 11, 2015:

Wrong sentence. I meant to say I do not smell antifreeze,have wet carpet or foginess.

theresa on May 11, 2015:

My 2011 jeep grand Cherokee puts out heat on the passenger side all the time. Everything on the drivers side works fine. Also the blower motor will just shut off for no apparent reason. Dealer is telling me it's the heater core. I antifreeze smell or foginess. Please help. They want a f I r tune for the part and 6 hrs labor. Am I getting taken cuz I m a woman?

alex19760328 on April 20, 2015:

Enjoyed the Read thx

Lori on March 27, 2015:

The fan on my 05 Jeep Grand Cherokee Larado would only blow on high, so the Jeep Dealership replaced the resistor - blower motor. It worked fine one all 4 speeds. Two days later, I accidentally bumped on the a/c. When I turned it off, there was no heat. It only blew cold air. The mechanic says I need to replace the heater core and that it's not related to the work they did. What are your thoughts?

mario on March 16, 2015:

i replace the heather core 5 tiemes in my car every 2 months star leaking.i have a 1999 ford crown vivtoria 'police interceptor"

MikeNV from Henderson, NV on February 07, 2015:

I personally wouldn't thing Heather Core until now thank you. I'd think Radiator or Water Pump or something else. Found coolant on the garage floor and it turned out to be leading Manifold Gaskets. Interesting to not that the smell could be related. Enjoyed the Read.

doris on January 31, 2015:

1995 Chevy blazer 4x4. I've had no indications of cold are or leaks. Mech took hoses off and told Me radiator is blocked and I need heater core after putting in new radiator. If left like this it would mess radiator again.

Melvina on January 26, 2015:

I've been lonkiog for a post like this forever (and a day)

d on January 12, 2015:

great article. nice simple language, easy instructions. Still gonna pay someone to do it but was wondering if I should get my own heater core. the shop wants 700 bucks and I can get one for 60 online. is there a difference between theirs and one from autoparts warehouse? 03 Jeep Liberty Sport 6cyl3.7 ltr


Hilary on January 09, 2015:

2002 Chevy Blazer was told it heater core windows fog terrivbly and smoly fumes come through vents but heater still works very well

Roger on January 08, 2015:

Why is my car getting a little hot and blowing cold air I changed the water pump, thermostat,radiator and belt but nothing has changed it's an 2002 grand-am gt 3400 V-6

Stephanie Robuste on January 04, 2015:

I have an 01 Malibu I've replaced the thermostat and the heater core thinking that would stop my car windows from fogging up but even after those repairs my windows are still fogging up.... What's wrong?

Kimberly on December 19, 2014:

My mom's car just got repaired because of either the radiator or the fan kept turning off. But now every time we turn the heater on in the car, it will be warm, but I can smell something sweet, like syrup almost. I was worried about it, but someone told me that it wasn't the heater core because it won't give you any warning before it damages and that the mechanics probably just accidentally spilled some antifreeze. I really don't know what to think.

teddy on December 03, 2014:

I own a 96 chevy corsica 4 cylinder. 2 days ago, on my way back from work, I smelled a very sweet humid icky smell (coolant) inside my car. I kept driving only to see that white smoke started coming from my vents and my car started rapidly overheating. I pulled over to let the car cool about 6 times on the way home. When I got home, I looked under the hood and seen alllll of my coolant was gone after just getting it filled 2 weeks earlier. I asked around and everyone kept telling me HEATER CORE HEATER CORE HEATER CORE. But everyone also kept telling me to look for the missing coolant on ypur passenger side floor. Its STILL DRY. I jacked up my car to find a leak and poured a gallon of water into the coolant compartment to do just that and quickly jumped under the car. But what I found was all of the water was pouring out thru a 1 inch pipe connected tp absolutely nothing right underneath the heater core. No leakage from actual core itself. I was wondering if you could tell me if that is still a heater core problem or something else before I start tearing my dash apart? Please and thank you. :)

Liz on November 18, 2014:

I am positive I have a heater core problem. Ironically, I started the day I got my car back from getting a fuel pump relay repaired. After paying a lot for the fuel pump relay, how much does repair of the heater core cost?

Tonya on November 10, 2014:

Why is my car blowing heat on drivers side only.... It's the duel kind of control

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