Updated date:

Why Is the Heater in My Car Blowing out Cold Air and Not Heat?

Author:

JP993 is a self-confessed car and motorcycle addict, having saved thousands over the years working on and maintaining his vehicles himself.

Now that the cold weather is back, we'll be whacking the car's heater on the second we turn the key. Or not if your car heaters are not working. They work by using the heat in the coolant system that circulates around the car's engine to cool it.

That sounds a little odd right? Well, when I say cool, I mean keep to an optimum temperature, around 80 to 90 degrees. So this is where the heat comes from, your cooling system. That's why you won't get heat until the car has been running for a couple of minutes. As the engine gets hotter, so does the coolant.

Because we rely on the coolant system to provide us with heat through our heaters, there are now a few components that can fail and mean that you'll never get heat out of your car heaters.

The most common culprit for your heaters not working is a faulty thermostat. These clever yet very simple and cheap contraptions regulate the water circulation on initial startup. They're easy to purchase and simple to replace if you have a little mechanical knowledge.

A Thermostat, which will be located near the top of your engine, sits closed shut when the water is at ambient temperature, so when the car is left parked up.

When you start your engine, the thermostat stops the water circulation around the engine. This lets the engine warm up quickly and get the oil to its optimum temperature, vital for a healthy engine.

As the temperature rises to around 60 degrees, the thermostat opens up and lets the water circulate around the engine and through the radiator.

All this happens in a matter of minutes in normal weather. If, however, your thermostat has seen out its days, it will remain open. So on initial startup, the cooling system is working straight away. Your engine doesn't have a chance to warm up and your coolant stays at a temperature that won't give you any heat.

I've talked about the most common problem that is causing your heaters to not have heat but let's take a look at a few other things that can be the reason.

To have heat, you need:

  • enough water in your engine;
  • a working thermostat,
  • a working heater and heater controls
  • a cooling system that doesn't leak.

If you take short journeys, and your thermostat is broken, you'll never get the engine hot enough to produce any heat. A little test you can do is leave the can running, stationary at home and take a look at your temperature gauge that should be in your dash.

Once you see it get to the middle turn on your heaters and see if you're getting heat. If you are getting heat, your thermostat needs changing.

If you can't get heat no matter how long you leave the car running, I'm going to show you some checks you can do to find what the problem is.

If you're not comfortable with mechanics then read still read on so you know what to expect when you take your car to a mechanics. This problem is relatively cheap to fix. Replacing heater matrix's or head gaskets are where the costs become high.

What to Check If Your Car Heater Blows Cold Air

  • Is there enough water and antifreeze in the engine?
  • Is the thermostat working?
  • Is the heating system blocked by an airlock?
  • Are the heater controls broken?
  • Is there a water leak?
why-are-my-car-heaters-blowing-out-cold-air

1. Is There Enough Water in the Car?

Your heater uses the heat from the coolant circulating around the engine. You should also have antifreeze in your coolant mixture, this not only stops the coolant from freezing inside your engine but also stops it corroding. The heater is higher up than the rest of the cooling system, and thus last in line for coolant. Thus the first thing you should do, if you have no heat, is to see if there is, in fact, enough coolant in your engine. You can do this by lifting the bonnet (the hood) and looking at the header tank, which collects overflow coolant from the radiator. This is a large tank, usually clear plastic, with a conspicuous cap, rubber hoses coming off of it, and "Max" and "Min" markings on it. It is positioned a little higher than the radiator, usually to one side or the other of the engine, directly above a wheel. If this tank is empty, you can fill it back up with ordinary water; you can add some antifreeze if you want. If your header tank is full then proceed to the next step. If you are not certain which is your header tank, ask a friend, or take the car to a local garage.

2. Is Your Thermostat Working?

As mentioned before, the Thermostat decides when to let water circulate around your engine. A simple way to find out if your thermostat is working without using any tools is to see if your temperature gauge is giving you a reading on the dash.

If the needle never moves or it's 30 minutes before it does, then your thermostat is most likely broken.

Your temperature gauge should be giving a reading or start to move within 10 minutes of starting the car. If you're noticing you're starting to get heat after driving a while this would also indicate the thermostat is broken.

If the nice warm heat doesn't last very long, this is because you're drawing the heat away from the circulated water. Check your temp gauge again and if starts to fall whilst you have the heaters on, the thermostat is broken.

They're cheap and your neighbouring handyman can fit one.

3. Is the System Blocked by an Air Lock?

Sometimes even with water in the system and a working thermostat, you can still get no heat; the flow of water in the heating-and-cooling system may be blocked by air or dirt.

One possible cause is an air lock in the cooling system. If your system has a bleed port or bleed screw, and you can find it, you can fix this air lock yourself. Run the engine until the fan kicks in. Once your fan has come on, look around the radiator for a bleed port or bleed screw. This is something that can be turned with a screwdriver. Once you turn it anti-clockwise, you should hear a hiss; this is the air being released.

4. Are the Heater or Heater Controls Broken?

Even though most problems with the car heater are not caused by the heater itself but by the cooling system or the thermostat, it is still possible the heater itself may be clogged or broken. Or the heater controls may be stuck or broken. In either case, there is a chance of a cheap or do-it-yourself fix, as shown in the video below.

Toyota Heater and Control Valve

5. Water Leaks? Find Them!

An engine that keeps losing water is a big problem, and not just because low water levels will keep your heater from putting out enough heat. A car that is not getting coolant will heat up and damage itself permanently. If it leaks water, you need to find the source. It can be a split hose, leaky radiator, the water pump, or even worse, the head gasket. Finding the leak can be a pain in the butt too, as even a tiny hole can let a lot of water out while the system is under pressure from being driven.

But if the weather is cold, that makes your investigation easier. Make sure the engine has run long enough to get good and hot and make sure the coolant is topped up. Then, if there is a leak, the hot water escaping will turn to steam when it hits the cold atmosphere. Open the bonnet (hood) and look for steam: along the hoses, where the water pump is, and along the radiator. Also look inside your car—if your windows steam up, or the carpet inside the front of your car gets wet, your leak could be inside the car, behind the dashboard. It could be the heater matrix itself (the heater core) or a split hose.

If the leak turns out to be in the radiator, you can save the cost of a radiator, at least for a while, with products that stop leaks in a car's cooling system. You can also buy a repair bandage for leaking hoses, but this is a temporary measure. Hoses are rubber and don't last forever; they have to be replaced every few years.

Sometimes water loss is caused by a knackered water pump. Telltale signs of a broken water pump include a constant rough metallic sound when the engine is running, or water trickling down the side of the engine. The water pump is a vital part of the engine, and if it's broken it needs to be changed as soon as possible. Often it runs off the cam belt ("timing belt"), and if the water pump destroys itself it will take out the cam belt and the engine along with it. Consider replacing an old water pump as part of routine maintenance, along with the replacement of the cam belt and accessory belts, if you have an old car and want to keep it a few years.

A leaking head gasket is the worst news at all; it means your engine has lost its integrity, and your car needs major repairs right away, assuming you want to keep it.

1. Diagnosing Heater Problems in the Jeep Liberty

So if you've tried all of the above and you still have no heat from your heaters in your Jeep Liberty, there are a couple extra things you can do for this model to get the heat bellowing back out of your heaters.

There is a downside: if you're not handy with the spanners you should take your car to the garage. But make sure you go with the knowledge below.

The Actuator Fix

If you're still not getting heat to your heaters, and you know the heater core is not blocked due to a clogged system, and you know there's no air in the system because you've bled the system using the bleed nipple on the right-hand side of the radiator, the last thing you can check is an electronic component.

The centre dial of your heater control located in the centre console can fail. This dial, which changes the amount of heat you want, is run by an electronic component called an actuator that controls the amount of hot air that enters into the car.

It's a pretty simple job that this actuator does. It opens and shuts the gate of the heater ducting: something a mechanical part used to do.

You can access this actuator in the left-hand foot well. It is the lower actuator that usually fails. Before you take anything off, look at where the actuator is located and mover the dial. If you can't see the teeth of a black cog move as you move the dial ( these teeth are just visible) the actuator is stuck or failed.

Remove the actuator and manually open the gate (you'll see the gear the actuator slips onto) by hand. When you see the gate open, run the car, and you should now have heat.

With the actuator plugged in still but not mounted, see if it moves freely. If it's not moving, time for a new one.

You can also test the actuator with a multi-meter if you're handy.

2. Diagnosing Heater Problems in the Jeep Wrangler 2012 (and Others)

The Jeep Wrangler has a heater actuator issue almost identical to that of the Jeep Liberty. This issue is described below, and then we talk about another known issue with sandy material that clogs the system.

The Actuator Fix

By checking this first, you'll save yourself a lot of time taking things off. The Jeep Wrangler, unfortunately, doesn't have as much access behind the dash as the Jeep Liberty does. But you can find out if you'll need to start taking your dash apart just by taking a look under the dash on the left-hand side.

As with the Jeep Liberty, the A/C to heat control is the centre dial on your dash. This opens and shuts the gate behind the dash to determine how much hot or cold air goes into the system. This is operated by an electronic part called an actuator. It simply goes up and down to open and shut the gate.

What you should do is look under the dash and look for a white plastic part that moves when you turn the dial. You may need a light to shine up in there to see it.

If you can see the white plastic moving, then the actuator isn't the problem, and your problem may be sandy sediment, as described in the next section. But if you can see the white plastic part and it's not moving, then your actuator has failed.

As I said, the location of this is a little trickier than on the Jeep Liberty. There is a panel that sits under the steering wheel on the left-hand side that you can remove to gain more access. It may not be perfect access it, but it will mean you can remove the actuator without removing the entire dash.

Once the actuator is removed you can manually open the gate by turning the gear the actuator is attached to. Run your engine, and after a few minutes see if you get heat with the gate now in the other position.

With the actuator off but still plugged in, see with a little push on the plug if it now works. If it does, you can decide whether you want to replace it or not.

The Sediment Buildup Fix

If your actuator was fine all along, you may be dealing with a very common and well-known problem, the buildup of sandy sediment in the system.

If you did all of my general tips and there was still no heat, you may want to try flushing the system again. Get the best coolant flush you can afford.

Make sure you dump out the old coolant at the lowest point possible: the left-hand side of the radiator at the bottom. It is tight on the Jeep Wrangler, but in order to get all the gunk out of the system, you need to undo the lowest hose to remove the coolant.

Once you've done this, leave the bottom hose detached, and run a garden hose through the top radiator hose on the right-hand side, going into the engine, to send fresh running water through the system.

Take the radiator cap off and do the same thing through the radiator (it'll come straight out the bottom hose.)

Now locate the two heater core hoses that are at the back of the engine and go into the firewall. Take both hoses off that attach to the metal piping and run the water through one hose, sealing it with your hand, with the flow going towards the windscreen, not down the metal pipes. You should eventually get the water to flow out of the other pipe.

Connect everything back up and fill up your coolant with antifreeze. You'll now want to bleed the system, which is tricky on these models but is the most important part of all of this.

Run the engine until it reaches the operating temperature and starts bleeding the system. If you bleed the coolant system properly you should now get heat from your heaters.

If you don't get heat, it is likely there is still air in the system. Check your heater core pipes for pressure and make sure both are heating up. You can get a garage to pressure-fill your coolant system.

3. Diagnosing Heater Problems in the (BMW) Mini One Cooper & S

Fixing the heaters on a Mini 2 (BMW) whether it be the One, Cooper or Cooper S, is relatively straightforward and something you can do yourself if you don't mind getting your hands dirty.

If your Mini is relatively old, say around an '07 or older, the reason for your problem could be this. The principle will work on all Minis though.

Over time, the water that is in the engine, which is being constantly heated up and cooled down, starts to thicken due to the elements that are in regular water. This is why your header tank will go brown.

With older cars, also, there's usually been some problems over the course of the cars life, problems like split hoses, leaky radiators, or front crash damage. The cheap fixes for leaky radiators are usually chemical-based products that are designed to fill the split or hole. This stuff will "gum up" to block the leak.

The thing is, the excess gum just ends up circulating around the system. So between that and old coolant, the system gets pretty grimy.

The Fix For Clogging

Get yourself a coolant system cleaner, or flush as they're sometimes called, and run this in your coolant system. Follow the instructions on the bottle for the best results.

As you let this stuff work and break up the gunk from the system, you'll want to undo the lowest coolant hose you can get to on the engine and dispose of this water correctly.

The heater cores on Minis as well as the thermostat are prone to clogging. Thermostats are cheap, so go ahead and replace this if you haven't already.

Now you want to refill your coolant along with some anti-freeze mixed in. Anti-freeze not only stops your coolant from freezing up, but it also stops the coolant from corroding your engine and lengthens the life of your internal engine parts.

You should now get heat from your Mini's heaters.

If you don't, there's one last thing you need to do, and that is bleed the air from the system. Mini's have their radiators located quite low, and so air is prone to being trapped in the system. Try a regular bleed of the system and see if you get a noticeable difference.

If you still have no joy, you'll need to take your car to a garage and ask them to pressure-fill your coolant. This should be a simple job for them and shouldn't cost too much.

4. Diagnosing Heater Problems in the Vauxhall Corsa

The problem with the heater on the Vauxhall Corsa (as well as the Renault Clio) is often that there is no power from the heaters at all. This issue has nothing to do with cold air coming out instead of heat. This loss of power is also a common issue on the Renault Clio. Or you may have a dirty fan that is stuck.

Fix for No Power to the Heater

The first thing you're going to want to look at is your fuses. On the back side of the fuse cover, there should be a table of what fuse does what. Find the one for the heaters and check to see if it hasn't popped. If you can't locate the fuse for the heaters, check all of your fuses.

If all of your fuses are ok, the next thing to go on to is the heater resistor. On the Vauxhall Corsa D model, this resistor is located underneath the glove box. You can get to it without removing anything.

You'll see a plug going into a white box with ridge lines on it. You should also see in front, to the left, a cylindrical grey plastic object, which is where your fan sits. When you've located the plug, turn your ignition on, put it in the "1" setting and wriggle the plug; you may find that the fan comes on. After you've tried this, turn your ignition off.

If the fan does come on after a wriggle of the plug, this means your resistor is faulty.

To replace the resistor, undo two bolts either side of the plug and remove it. Get the part number off of it to make sure you get the same resistor as a replacement. Put in the new resistor and give it a try.

Fix for a Dirty Fan

If the fan didn't come on when you turned on the ignition and wriggled the plug, your resistor may or may not be faulty, but it's also possible that your fan itself is the problem. Dirt may be covering the terminals inside the fan and causing it not to connect properly. To fix this you can simply clean the terminals inside the fan.

You're going to have to remove the glove box to remove the fan. The glove box is held in by four torx bolts, one in each corner. Once you remove it, you'll see the ducting from the fan to the back of the centre console. Now locate all the bolts on the fan housing and remove the plug.

Once you have the fan out, look inside it, and through the hole where the ducting attaches to see any dirt buildup. To clean the terminals, hold a rag inside this area while you manually rotate the fan. You should see a noticeable difference.

Now, plug the fan back in but don't mount it yet. Put the fan position on the switch to the "off" position and prop the fan up making sure the fan housing is not touching anything. Turn on the ignition. Switch the fan to the "1" position, and it should spin. Be prepared to turn the fan off almost instantly.

Now that you can see your fan working turn off your ignition and replace everything. Remember to put the ducting back.

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.

Comments

JP993 (author) from England on January 23, 2020:

You may have a problem with the gates that direct the air from either your heater or your air con. It's a common problem for newer cars to have stuck gates which are located behind the dash and not always easy to access. Check online to see if it's common problem for your vehicle.

Josh on January 16, 2020:

my 2011 avalanche is blowing hot air on the drivers side and cold air on the pass side, and yes the temp is set at 24 for both sides.

Bob on December 19, 2019:

Car is warm, turn heater on , warm air comes out. A few seconds later cool air. turn it off then back on its warm then cools off again.

Kayla on September 27, 2019:

What would i do if i put it on thr heater and it blowes out cold air all the time.

Lydi on August 15, 2019:

Thank you for this awesome article! We were freaking out about why the car wasn't warming up and you helped us a bunch!

Shirley on April 08, 2019:

Lost coolant and engine over heat

David on January 02, 2019:

Brilliant. Absolutely brilliant. Clear, easy to follow instructions that even an inept knuckle buster like me can follow. Thank you.

Robert Bailey-Whitten on December 05, 2018:

My 2014 Jetta is blowing luke warm from the heater then it turns to cold air why??

Jason on May 12, 2018:

My heater in my vp calais its not working from the climate control the hose in the car are hot but blowing out the heat

Frankie on May 04, 2018:

I have a 99 ford focus diesel no heat and car only overheats when driving in idle no problem ?

Ian on March 18, 2018:

Been told my fiesta 03 radiator is blocked do I need to replace the radiator

Tracey on March 07, 2018:

Engine overheating warning light on and smell of burning any idea what this is?

Glen on March 06, 2018:

No leaks temp gauge works and fan comes on just no heat out of heater

Kris on February 21, 2018:

Just took our 2015 Ford Expedition to the dealership and had an AC flush done and as soon as we drove away we noticed that one side of the car only puts out cold air, despite it both thermostats on the dual air control being set on heat. Dealership said they did not cause this and will charge us $750 to correct. Is it possible they did something when performing an AC flush?

Edward on January 13, 2018:

Hi i have 2003 3.8 town and country that blows very low heat when it idles and starts cooling down when you drive it .please help me with this issue you can watch the temperture needle inside car and as you drive it goes back to the c positation

JP993 (author) from England on January 03, 2018:

So it doesn't give you any heat when fully warmed up and the car is idling?

JP993 (author) from England on January 03, 2018:

Was the system bled to release the air from the system?

Jesse on January 01, 2018:

Okay I change both of thermostats in my car and it still blows cold unless giving it gas then it'll blow somewhat warm does anybody know the problem

Cindy Webb on January 01, 2018:

I have a 2000 Lincoln change the radiator and the thermostat and I still don't get no heat

JP993 (author) from England on January 01, 2018:

Try a thermostat.

bass on December 20, 2017:

i have an audi 1.9 td 2001. my heater started to blow cold so checked water bottle it was empty couldnt find no leaks any where. any one no what may of happend to the water.as the exact same thing happend about a year ago i topped it back up and not had any problems since till today?

Sandro on December 18, 2017:

I have Honda pilot 2004. I have a small leak in the radiator in September. I used irontite to fix it. Now in December , there is no heat in my truck ( very very weak).

The mechanic told me it is because of iron Tite. He performed back flush for the radiator and for the heater core. No heat. He changed my heat control valve no heat. He changed the thermostat with oem thermostat ... No heat. Finally he changed radiator and guess what ... No heat. Any advise on what the problem can be or what is the solution .

Laura on December 16, 2017:

I have a 2002 Ford Taurus that I bought used to get my husband to and from cancer treatment so 140 miles 2 times a week.the car runs like a dream except for the heater .The car warms up and you get sort of warm air but if you put the fan higher it starts blowing colder all this time it stays in the middle between hot and cold.we paid 75.00 to have the thermostat replaced no change.We are on disability due to cancer and don't know what to check for next.

liz420 on December 16, 2017:

i have 2005 hyundai tucson. And when i turn on the heate, i get nothing but cold air. radiator was changed this year.

Michael on December 13, 2017:

2000 galunt heater blows warm for a few seconds then starts blowing cold turn off 5 mins back on warm a few more seconds

Anonymous Helper on December 11, 2017:

RICKY Did you change the thermostat? Always do when you do a coolant flush every 3-5 years or 10 depending on when your car needs it's coolant replaced. The thermostat could be stuck in an "open" position cycling the coolant through the whole system, thus, not being able to get heat for a long time. If you still don't get heat it's best to get the coolant system diagnosed by a trustworthy mechanic to find out what is wrong. Good luck!

BRYAN boyette on December 10, 2017:

having problems with heater in a 2000 plymouth grand voyager blows cold air.

Ricky on December 03, 2017:

I just got a radiator and engine flush but my 2001 Chevy blazer still blows cold air what can I do.

nicky on November 30, 2017:

hi I have a 2012 corsa, it's been blowing cold air for a few weeks now, it's strange bc after about 20 minutes of driving it warms up a little, can anyone help?

thanks in advance.

Scott on November 24, 2017:

We had a radiator replaced over the summer the air works fine but now even if we let our car warm up and drive it all day the heat never blows out hot it's always cold the other day I noticed when the heat was completely turned off but it was on defrost and it was blowing a little warm but as soon as I turn the heat on it got cold again I'm assuming it's the thermostat could you tell me if you think that's the problem

lynne holland on November 19, 2017:

I am a 76 year old women and I am trying to make it with SS and food stamps . So far no heat since our temperatures have dropped. read your suggestions and Hope I can do this . Heat would be nice !!!! Thanks

Barry on June 02, 2017:

Hi my car heating is on full but it blows hot for a few minutes then cold before going to hot again. The coolant light is on but the tank is full. Any suggestions?

Nadeem Ahmed on May 25, 2017:

Please any one can help me. I am honestly fedup..i have got skoda octavia mk1 57 reg..

i had problem with car heating up and i have changed thermostat 3 times temperature sensor, new fan, fan sensor, new radiator, water pump timing belt, head gaskit, changed water bottle and cap infact everything except heater matrix.. the car didnt get heat up so solved but when i stop in rush temperature gauge goes to 90 and comes down wen i start driving bit. The heat was not enough except little bit warm in the car. I talked with mechanic he said lets change thermostat geniune one and it cost me £23. After that wen i drove it there was. No heat at all and temperature gauge was at 90. I stoped and open water cap all antifreeze came out with pressure and emptied. Again builting pressure.

If any one has got skoda experience plz let me know wot shud i do. I am badly stuck as its taxi and i m making big zerooooo...

Rhonda Wyatt on May 06, 2017:

03 Mitsubishi galant. Heat only works when it is warm enough out to not need it. When the weather is cold so is the air from the heater. What could cause this? Lack of coolant?

Linda on April 25, 2017:

When my heat is on warm/hot air is coming out of the passenger vents - as it should; but the air coming out of the vents on the drivers side is cold. Again this is when the heat is on. What could it be? My car is 2011 Chevy Impala

William Reed on February 18, 2017:

Hi my name is william and i have a 2005 dodge magnum. I changed my whole cooling system in my heater still doesn't work can you help me with the problem

Jeff on January 27, 2017:

I have a 2012 Mini. Have had issues with the heater only blowing out luke warm to almost no heat. They replaced the radiator, temp sensor, fluids, said water pump is fine, etc. Each time they do a fix the heat works great for a few days and then one day will just start blowing air that isn't as warm again. Any advice?

Jose Guerrero on January 21, 2017:

I have a 2004 Nissan Titan truck. The heat will only blow warm if I am driving full speed. If I slow down, stop, or it is parked, the heater blows cold. The engine temperature warms up after it is started, but the air still blows cold.

Xiomara Mota on January 20, 2017:

thanks so much, I learnt a lot.

Joan Day on January 19, 2017:

Thank you so much this was very helpful to me.

Michael Hinchey on January 16, 2017:

Hot air takes awhile to get into the cabin but takes a lot longer to get somewhat warm on the passenger side. Then after a little bit cold air blows on both side, esp at idle. . Any ideas?

trekkiechiq on January 15, 2017:

I just replaced a bad heater core in the summer, and everything was fine. We had heat when it was selected, and we had cold when it was selected. A/C doesn't work, but that's an A/C issue, not related. This winter the heat was working until one morning I went to warm up the car, and I always keep everything off and set to cold until the car is warmed up. Once it was warm, I turned the dial from colder to hotter and it stopped blowing, then started blowing again, but with no heat and it hasn't blown heat since this occurrence. Is this most likely an actuator issue? Or would one of your above mentioned issues be a possibility? It's a 2006 Grand Prix, 3800 Series III, 3.8L V6.

Michael Hinchey on January 15, 2017:

I have an 06 Subaru Tribeca limited.

Very good article. I am having an issue with the passenger side takes much much longer to heat up. When I put the defroster on, the car start blowing cold air even after the car has had heat. Any ideas?

Ashley verstraete on January 08, 2017:

I just got a cheap car from a guy. Wasn't running for a few months. Heater ran great for the first week I had it except I had a squealing so someone told me to turn the heat over to ac and see if it stops the sqeal. I did and then switched it right back over to the heat and the heater stopped blowing hot air. As a minute before that we got hotter then ever in the car with the heat on. I think something is stuck. Its a 98 Oldsmobile intrege what do you think?

David Theriot on January 07, 2017:

Maybe you can help. I bought a truck that was suppose to have a working heater, the fans blow in the truck but it's freezing me out. I have a baby an can't be riding with it 20 degrees out. What do I do? I'm somewhat mechanically inclined but this idk anything about. Please help

Richard on January 06, 2017:

Thanks that was very helpful

Walter88hall@yahoo.com on January 02, 2017:

I Have a 1993 Cadillac 60 special! No heat at all! Have driven to Calif many time from Utah no over heating problems what so ever! Just blows cold air! In the summer it blow hot air! Go figure!

jacque on December 31, 2016:

on my ford explorer, we have no heat, no water leaking into the floor board so we changed the heater control valve and the thermostat, still no heat it doesnt look like there is any water movement though, possible water pump issue? car doesnt overheat at all

Steven on December 30, 2016:

My car will only start producing hot air when I floor my car and only sometimes when I'm just sitting there. What do you think the problem is?

deeerite616 on December 19, 2016:

This is by all means the best site (blog) i've came across. very very helpful. i cant wait to throw all this information to the shop that's trying to rip me off. i have a 98 escort. always have and still do take care of it. June 2016, new water pump/timing belt. september over heating. went to prior shop he said it was head gasket. $900. here it is december i'm not getting heat. took it to him for over heating now no heat. he changed thermostat still no heat. today he tells me he had to change the "coolant temperature sensor" i did my research & it seems that has nothing to do with my heat being cool and not hot. charging me $85 i looked up the parts & they did not go more than $25. should that part have been changed when gasket was done? i'm not paying him anything bc i clearly see this is scam.

Jerzey on December 16, 2016:

I just bought a 91 Dodge Stealth, everything was working fine. Had the car about 2 weeks when the heat stopped blowing hot, temp gauge hardly moves, any known problems with the stealth and heat? Thank you so much

senajj on December 15, 2016:

Both heater hoses are hot. Switching from heat to defrost, works.still blows cold air.

Evan on December 11, 2016:

Hi, I have a 1998 ford expedition Eddie Bauer with the 5.4L V8, and I don't have any heat in the car, I'm pretty sure it's not the thermostat because the car does get up to operating temperature, and the temp dial does show this as well, no smells or anything so I don't think my heater core is leaking either, what would you recommend I check first to figure out the problem?

tiredpadre on December 10, 2016:

I have a really nice pontiac grand am. for a while there, it would cook you out of the car. Now it blows the coldest air you think of. the tank is always draining out, but the oil is nice and clean. I was told to change the pump out. When it starts to heat up or go into overheat, the car loses power. But when it goes back down from overheating, the power comes back, but at the same time, I still have cold air blowing out. The mechanic here wanted $3500 to put a new rebuilt motor into it. I bought it as is from dealer. thye refused to help or return it. I still owe anotehr 8 years on the loan.

Jimmy on December 10, 2016:

my car heaters are blowing luke warm, i have checked pressure, thermostat and heater core but no change

Leo on December 09, 2016:

Hi! i had a toyota sequoia sr5 2004 blowing cold air instead of heat i already change the thermostat flush the heater core but still blowing cold air the back has hot air what's the problem with it?

Jenna on December 08, 2016:

My heater only works when I'm driving, if i even stop at a red light it starts blowing cold air

Please help

2007 Chrysler 300

Jay on December 05, 2016:

My fiancé' so grandmothers van blow heat in the summer but stopped as the temp started dropping into the 50s and as it kept dropping it still won't work

Debbie on December 03, 2016:

I've a Clio 2001. The heater blows cold air. Thought was head gasket, put steel seal in it , car runs now! Tried bleeding the water system. A lot of air came out and slightly warmed but went cold again!! Any ideas please

Destiny on December 02, 2016:

Okay so I have a 2002 Jeep Liberty and I bought it maybe a month ago the person I bought it from replaced the heater coil right before I bought it the first few days my heat worked amazing now it's just blowing cold air what should I do

Eddie on December 02, 2016:

So... 1997 Explorer 5.0 V8 and living in Alaska. Block heater, oil pan heater, and battery heater plugged in all the time now. Coolant levels are fine and mixed for -70. Outside temp -20 to -25 one morning and started it... engine warms up to operating temp just fine after 20 min and no heat, ice cold air so air is blowing inside the cabin fine. Not a blend door problem, because i have it forced for heat only. Didn't drive it to work that day. Started it up later on after work. Engine warms and begins to overheat after 20 min and still not blowing hot air. Turned it off. Outside temp got above 0 one morning. Started it up.. it starts blowing hot air within a few minutes, but engine is operating at a low temp, close to the Cold mark. Thermostat? Water Pump? Blockage?

Niki on November 28, 2016:

I have a Mazda 6 made in 2010. I bought it 5 months ago with 50000 miles. The car heater is blown cold air and the warm air then old air then warm air again. Recently I heard watery sound when I stared engin top up cooling it's stopt. I heard clicking noise under dashboard been fixed. But still have problems with my heating. Does someone has any idea what could be wrong? I would appreciate any help please. thanks

JP993 (author) from England on November 23, 2016:

Hmmmmmmm. sounds like a blockage.

JP993 (author) from England on November 23, 2016:

Hello Lisa,

Im not familiar with the car but does it have separate controls for each side of the car, such as the passenger wants heat and the driver wants cool air? There are some videos on youtube on how to use the Juke heaters, which leads me to think they have a over engineered control system. Which might be the cause rather than a fault.

JP993 (author) from England on November 23, 2016:

Hmmmmmmmmmmm a water pump with a faulty impeller could stop your water circulating through the heater matrix but you would usually have some tell tale signs of a dead water pump such as a whine or leak. You could take off a top hose ( when the engine is cold ) and start the engine and see if the water gets pumped out the hose. If not then you could have a faulty pump.

Jim Miller on November 14, 2016:

I have a 1998 Ford Expedition 5.4 V8 engine, It is blowing cold air, no heat. We have replaced thermostat, radiator cap, blew out the heater core, attempted to get any air in the system, out. I have been told to try and replace the water pump. The pump is not leaking or making noise. Will a badly worn impeller on the water pump be my problem. Sometimes the heater will blow out hot air and work beautifully, other times cold air

Any ideas

Shane on November 04, 2016:

I have a problem with my Vauxhall corsa the heating blows out freezing when on hot I can't seem to find a leak I have changed the thermostat with no difference I'm at my wits end with iv tryed to bleed the system but dose not have bleed nipple or I can't find one so did it with water cap off while squeezing the pipes yet heating still don't work please also I was told the air con needs topping up as had o ring replaced but I don't think that has any affect on the heating dose it

Lisa juke on October 27, 2016:

Hi I have a Nissan Juke 2013 plate, only bought 2 months ago. The passenger side blows very hot air whilst the drivers side blows Luke warm air. What could this be as the coolant fluid is full.thanks Lisa.x

Ben on October 14, 2016:

Very helpful, I bought a new thermostat for my 2002 Hyundai Accent and it warmed my heater and brought the temperature gauge to operating temp

Amanda on October 13, 2016:

My 2005 Toyota Matrix X-rays. My heater is not that hot on the driver side and on the passenger side car in t is cold. Can u please tell me what the problem of s. My car does not over heat. The hoses going to the heater core r hot under the hood and they r hot in the cabin. Need help please

s.rose on September 18, 2016:

Very helpful article, specifically the workings of the thermostat and coolant.Now i know if the thermostat stays open, you suffer (no heat) and if it stays closed the engine suffers, it doesn't cool off.

Ashley on July 27, 2016:

OK so my problem is I have a 2001 Chrysler town n country 3.3L. I have to put water in my van every day I don't see any leaks besides when my air is on. My heat does not work it blows cold air and the heater and air only work on high. It use to work months ago on every setting but always made a really loud noise when on until it only worked on high still make a kinda loud sound. I have checked for leaks but can't find any. Just not sure where all the water goes so fast with no leak. I'm temp gauge works great I had replaced the radiator cap not long ago and my fuel cap because my check engine light was on saying there was two leaks I cleared the codes after I fixed both and check engine light hasn't come back on... I'm so lost any suggestions would b great thank u

Phil on July 10, 2016:

I've got a 2000 Mazda Familia 2 litre Diesel. Radiators full, gauges work, new thermo' , water circulates but got only very low temperature heat.

Flushed it out 3 times over the last few months and still no heat.

Some years ago I had a slight leak from the water pump and put a "stop ;eak" stuff in. Could this be the problem and if yes how do I now sort it?

Leecia on June 14, 2016:

Well this helped alot... i do have a water leak on my Jetta 4 and i figured the heater is not working because of that... this confirms it.. i need to get it sorted out asap.!!

bill on May 29, 2016:

I didn't read all of the posts so this may already be in there. A stuck thermostat is the most likely culprit. However, it can stick open resulting in the water never getting warm enough to supply warm air to the interior or it can stick closed resulting in the car overheating. The above BMW problem could be a thermostat or vacuum leak. Vacuum holds the heat door open or closed. When you let off the gas, you supply enough vacuum to allow the heat door to open and when you give the car gas, the door closes.

robert on May 19, 2016:

My car no matter how long it runs still blows cold air and win the water timp gage goes up just a little as sewn as I turn it on it hose down I would like to no the problem

Ben on April 24, 2016:

I have a 1997 honda civic lx 1.5 5 speed and it blows cold air and overheats. It has a new timing belt and water pump. Semi new head gasket and thermostat and the radiator was just flushed. Any ideas?

nick on March 04, 2016:

just bought a 01 astro and tonight for the first time out of no where i lost heat added anti-freeze and got heat back but i dont know where the water is going no leaks as i can see and runs like a champ? it does have rear heat but dont know if any leaks r in those lines

The Logician from now on on February 11, 2016:

You do know millennials will read this, you forgot the most important of instructions that they need to know.

TURN THE CAR ON AND GIVE IT TIME TO WARM UP.

Great hub page! Must keep for future reference.

Shay on February 03, 2016:

thank you very helpful. Where is Facebook like ?

Martine on January 28, 2016:

I have a Nissan sentra 2004. When starting it cranks but takes a while to start you have to pump the gas to help it start. Secondly the heater does not work, blows cold air. When you drive it jerks and when you stop at traffic light it it rocks back and forth and on acceleration you need to step the gas slowly otherwise it will lose power - it drives on slow speed. I took it to Evans automotive and they said the problem is; the sensor is terminated at the wrong end, there is a head gasket which blew due to overheating, but i have never experienced over heating on that car. It does not overheat now. One of the things they said was the coolant was empty, i checked the radiator and it had not water. Yet previously I had put in antifreeze. So i filled some water on the radiator, them i saw steam coming out of the engine. When I opened the bonnet I found coolant and water spewed all over the engine. I poured water again and I saw the leak of top of the radiator edge. Now it the the diagnosis of Evans correct or they did not see the problem with the Radiator. What exactly is the problem and what should i do first?

Matt on January 25, 2016:

My nissan heater only throw hot air when it's moving. When it's on park or at a stop sign it throws cool air... can someone tell or explain what's wrong

araceli on January 15, 2016:

Hi! I have a 2005 Chrysler Pacifica and the left side of my car's heater blows out hot air and the right side cold. Do you know what the problem might be?

Austin on January 13, 2016:

I have a 2003 Mazda 6. I let the water temperature get warmed, and my heat works, but after about 5 minutes of using it, it'll blow cold air and the water temperature gauge drops back down. Once I turn of the heat it'll rise up again and the cycle continuous

JP993 (author) from England on January 13, 2016:

Hi Ashley and Jarrett,

have you tried flushing the coolant? there could be a blockage.

jarrett on January 07, 2016:

I just changed my thermostat in my dogde derango it blows light heat out but then blows out cold air again what can be fhe matter

Ashley K. on January 06, 2016:

Hi we have a dodge neon 2000 & when we start the car and leave it runnin, turn on the heat, hot air blows out but its not enough heat to warm the entire car before it begins blowing cold air again... We've replaced the thermostat, addded coolant, checked the radiator and controls, but we can't seem to find the problem nor fix the "no heat" problem

Any ideas as to what we could do or look at to find the problem? & how to fix it? Thank you!

JP993 (author) from England on December 15, 2015:

Cindi you may have a head gasket issue. Take your oil filler cap off, see if the oil is creamy or have a garage test for oil/fuel in the coolant.

Jeanna on December 14, 2015:

I replaced the thermostat put antifreeze cleaned the radiar and it still blows cold air i have a 96 saturn

Margie on December 13, 2015:

I need help as my heater is putting out cold air. I know the switch is broken and if i switch it just right it cstches and out comes hot air. Well the other day i changed it subconsciously and now cant get it to catch back. I do not have 500.00 right now that the mechanic says it will codt to pull the dash and fi . Is there a quick cfix for now? Thank you.

Luc Gratton on December 06, 2015:

I set my heat control to high, the fan to high, in the morning I start my car from the house with the remote starter, after 15 minutes I go in my car and sometime the air coming from the heather is cold, if I turn the heat control to cold and then back to hot then hot air come out, my garage change the motor and adjust everthing and it happen again sometime, they don't know what to do anymore, it is quit frustrating on a cold morning

Cindi Best on December 06, 2015:

My car is over heating and heater blowing cold air changed thermostat not leaking any fluids no fog or wet floor it only over heated once then i parked it could this still cause sirious damage

melinda on December 04, 2015:

My truck is a 2011 chevy colordo and the heat or a/c will work. It will not blow and the blower is good the heater coil is good. We dont know what esle to do

JP993 (author) from England on December 04, 2015:

Hello Irene,

This sounds like a mechanism problem which would require removal of the heater matrix. $1000 sounds a lot but this could be a very labourious job. Not difficult just time consuming.

Irene Galligan on December 02, 2015:

Hi I own a 2003 Mitsubishi Lancer heat was fine until 3 yrs ago. The black button turns left easily for cool air but won't turn right for heat. I did some research found many others who had the same problem. I brought it to one mechanic who said he would have to remove the entire front console to fix it. This would cost a lot like $1000 which I thought was crazy so I gave up. My son drives it now I beg you can you tell me what I should do to fix it. Thank you.

JP993 (author) from England on November 26, 2015:

John K,

You could have a broken heater matrix, the bearings in the fan could have potentially failed.

Rose and Lauren,

Sounds like there is a common issue with 2000 Dodge Caravans. Heaters on these cars need to be recalibrated from time to time, a garage should be able to do this. The mechanisms are also mechanical which change air from hot to cold. These may be warn.

Lauren on October 22, 2015:

I have a 2000 dodge caravan. The heat and air blower comes on and works but its just air. We know the switch for where it blows is stuck on the defrost vents but thats a later issue. The main issue is getting the heat to work. We are going to try to flush it first bf the heater core but wanted to ask in case there is a quick fix

John k on October 14, 2015:

2002 ford explorer. Clunking / banging noise that changes tone or goes away when adjusting temperature knob. Engine temp is normal on gauges, but most of the time still blows cold air.

Rose Mitchell on September 20, 2015:

I have a 2000 Dodge Caravan i replaced the thremast top off the fluid and i have no heat just cool air blow's out the temperature gauge reads normal what could it be?

Monica Madrid on August 07, 2015:

It blows out just cold in both why