Updated date:

Chevy 3.1-Liter Engine: Leaking Intake Manifold Gasket and Warped Heads

Upper intake manifold, Chevy 3.1-liter engine

Upper intake manifold, Chevy 3.1-liter engine

The Chevy 3.1-liter engine has a notorious weakness, a failure mode that GM will not cover after the warranty expires. The lower intake manifold gasket fails and leaks coolant into the engine oil.

I had the dealership replace the manifold gasket the first time at about 40,000 miles before it got to the point of leaking coolant into the oil. This cost me $1200, mostly for labor. Then, just 15,000 miles later, the gasket failed again. This time coolant leaked into the oil; the giveaway was the milky substance that could be seen on the oil filler cap.

Realizing I was looking at another repair bill over fifteen hundred dollars, I decided to do the job myself and do it right. The first time, I didn't do the job myself because I didn’t have the time; also, I was a little intimidated by the fuel injection system, two intake manifolds, the special tools I would need to complete the repair, and the manual’s complicated procedures for removing all the different parts of the upper engine. The time element was a reasonable excuse, but the intimidation element was not. If you can change your own oil, replace belts, and change spark plugs and filters—which is a basic tune-up—then you can do this job.

How to Prepare for an Intimidating Repair Job

This article will not take you step-by-step through the process of completing the repairs; you will need a manual for that. But this article will help you avoid some common mistakes everyone makes when they work on their car. We learn from our mistakes and believe me I have learned a lot. A little more preparation in the beginning will save you a major headache later.

Before you begin the tear-down, you will need to do some preliminary research. First, go to the auto parts store and buy the repair manual for your make and model car. Next, pick up a few car magazines. They usually have articles on replacing intake manifold gaskets and rebuilding cylinder heads. The articles are easier to read than the manual. You can find even more articles archived on the websites for these magazines. Once you have read as many articles as you can find, you will realize that pulling the heads off of any car is a rather straightforward process.

Now you need to see if you have all the tools you need to do the job. A basic toolbox with socket wrenches, box wrenches, flare wrenches, and screwdrivers should cover most of your needs. Just make sure they are metric since most cars today have metric nuts and bolts. You will need some specialty tools; however, most auto parts stores have a rent-a-tool program, sometimes at a nominal cost and sometimes for free. For some tools, there is a hefty deposit, but it is credited back to you when you bring the tool back.

I would suggest that you consider buying a breaker bar; it is a must to break (loosen) the head bolts. A torque wrench is also worth the expense; the click type is better than the bar and scale. The torque requirements of the head bolts and the lower intake manifold bolts are specified in the manual, and should be followed, since the head is aluminum and thus a little vulnerable to damage. If you over-torque the bolt you can cause the bolts to break; if you under-torque the bolt it may cause the gasket to leak and you'll need another repair.

Get your digital camera out and start snapping pictures of the engine. Take pictures of every wire connection you can see. Don't say, "Oh that’s so obvious, I don’t need to take a picture of that." Trust me, it will save you hours of frustration later. Next, get a roll of blue painter's tape and a red sharpie; this will allow you to label every connection. I suggest red because the tape will get dirty and make the label hard to read. I label connections as "A to A," "B to B," "C to C," and so on. Take a picture of every part before you remove it, then take a picture of whatever the part came off of. The more reference points you have the better.

Zip-lock bags are a must. Put all the nuts, bolts, small gaskets, and small parts you remove into a bag; then label the bag with the name of the particular part. Seal the bag and put it in a safe, clean area where it will not get lost or moved. Following this practice, you won't waste time looking for a part later on when you are putting the pieces back together.

You will need some miscellaneous items, all of which you can get at an auto parts store:

  • container for the coolant
  • container for the oil
  • a floor jack
  • two jack stands
  • mechanic's magnetic pick-up tool
  • socket extensions
  • socket adapters (1/4 inch and 1/2 inch)
  • a magnetic fluorescent drop light

Set up a workbench (two saw horses and a couple of boards will do the trick) and pick up some kitty litter.

Once you have gathered all the necessary tools, you are now ready to begin the job of fixing your own car. Follow the manual carefully. If you're not sure about a procedure, take a break and re-read the procedure again. After the second or third read, the procedure will make sense.

It looks complicated.  Go slowly and keep checking your manual.

It looks complicated. Go slowly and keep checking your manual.

Dissassembling the Chevy 3.1-Liter Engine

The basic steps in the tear-down are not difficult. With the engine completely cooled, disconnect the negative battery cable, drain the oil out of the block into the oil container, and drain the coolant into the coolant container. Make sure you drain enough of the coolant out of the engine so that when you take the heads off, the coolant will not spill over into the open cylinders. (Here is where the kitty litter comes in handy; spread it over any spills you make, let it absorb all the fluid, then sweep it up and the spill is gone.) Spray all bolts that look rusted with WD-40. I'd do this the night before; it will penetrate the rust and make loosening the bolts easier.

With the car drained of fluids, you are now ready to begin removing parts. Remember to take pictures and follow the manual’s procedures. The order in which you will take off parts will depend on your make and model. As an example, the video below shows the disassembly sequence on an ‘04 Buick Century. On my '02 Chevy Malibu, the sequence begins:

  • Disconnect the air cleaner.
  • Take off the plenum.
  • Disconnect the PCV valve and push it out of the way.
  • Disconnect the heater bypass hoses and clamp them off (or jam sharpie pens into the hoses, this works just as good as a clamp).
  • Disconnect the thermostat by-pass pipe and remove it. Be careful with the quick-disconnects on those hoses, they break easily. (The good news is a replacement quick-disconnect is inexpensive, maybe five dollars at the most).
  • Last, disconnect the thermostat housing.

Accessing the Lower Intake Manifold Gasket on a 2004 Buick Century

Removing the Ignition Coil Pack

Removing the ignition coil pack is going to be your first area of self-doubt, but don’t worry. Keep on working and start disconnecting the spark plug wires from the spark plugs. Label each wire with the cylinder number it came off of. If you do one at a time and label each wire, you will not have a problem. Leave the wires connected to the coil pack. The coil pack is connected to a plate which fits over two posts, coming out of the head, and is bolted down with two nuts. Remove the nuts and lift the pack off the posts. You'll see the electrical connection that goes to the fuel rail; label it and disconnect it.

ignition coil pack

ignition coil pack

Removing Upper Intake Manifold and Valve Covers

You are now ready to remove the upper intake manifold. Depending on the make and model of your car you'll have to remove either six bolts or eight bolts. After you remove each one, bag it and label it.

The next step is to remove the valve covers, four bolts to each cover. The only one that will give you any trouble is the bottom bolt of the rear cover on the driver’s side. Due to the post for the ignition coil pack, you cannot use a regular socket wrench. You’ll have to buy a ratchet box wrench—I think I needed an 8 mm wrench. Otherwise, you’ll be fighting the bolt and rounding its edges. If that happens, you’ll never get the bolt out.

Valve covers after removal.  The yellowish creamy gunk means coolant has gotten into the oil.

Valve covers after removal. The yellowish creamy gunk means coolant has gotten into the oil.

Removing Exhaust Manifolds, Fuel Rail, and Alternator

I decided to take the exhaust manifolds off next because I was a little intimidated by the fuel rail and wanted to leave it for the next day. The exhaust manifolds are not difficult to remove; just follow the directions in the manual, and you will have them off in no time.

The fuel rail is actually very easy to remove. Just relieve the fuel pressure in the line (with the pressure relief gauge you rented), disconnect the inlet line and the regulator line, and pull up on the rail; all six fuel injectors will pop out. Replace all the O-rings when you reassemble the fuel rail.

You will have to remove the alternator. The manual is very straightforward on removal and installation. The tensioner pulley is released by using a ¼ inch ratchet (no socket attached) with a short length of pipe on the end to give you enough leverage to release the tension. Don’t try to release the tension without a short handled extension on the ratchet. You will not have enough leverage.

Removing the Lower Intake Manifold

The lower intake manifold is the tricky part. You have to jack up the motor and remove the passenger-side motor mount in order to remove one of the bolts from the intake manifold. The power steering reservoir is bolted to the block right over one of the bolts to the lower intake manifold. To take the reservoir off you need to remove the motor mount.

First, loosen the motor mount bolts with the breaker bar just enough so they'll be easy to turn when the engine is jacked up. Get the floor jack and a short piece of hard wood. Place the wood across the bottom of the oil pan towards the edge of the passenger side. Slowly jack the engine to take the weight off the mount. You can now remove the mount completely. Once the mount is removed, you will have access to the power steering reservoir attaching bolts. Follow the manual’s direction to remove the bolts and move the reservoir out of the way. DO NOT disconnect any hoses. Re-attach the motor mount and remove the jack.

You now have access to all the lower intake manifold bolts; just follow the directions in the manual. Remove the bolts in the numbered order given in the manual. Take a piece of cardboard (for example a cardboard box used to ship copy paper), and each time you take out a bolt, punch a hole in the cardboard, push the bolt into the hole, and label the hole with its number in the sequence. Once all the bolts are removed, the lower intake manifold is ready to be taken off and set aside.

The source of the problem:  bad intake gaskets

The source of the problem: bad intake gaskets

Removing Cylinder Heads

One of the problems with aluminum heads is that they warp very easily. If you have gotten this far, you might as well remove the heads and send them out to a shop for reconditioning. At the time of this writing, it cost me $140 to have the heads checked, cleaned and milled. Since they were in fact warped, it was worth the money.

The cylinder heads are not difficult to remove at all. First, remove the valve springs so you can pull out the push rods. Next, loosen the bolts, in sequence, a quarter of a turn, until you can turn them by hand. Remove the bolts and place them in the cardboard holder. Make sure you number the bolts in the right sequence. You will need to remove the lifter retaining guides. Each one is held in place by two screws. DO NOT forget to put them back in, or you are going to have major problems.

The heads are ready to be removed. A word of caution here: these aluminum heads have locator pins that can be lost very easily, so be careful when taking the heads off. There are two on the rear edge of each head. These pins help to properly place the head gasket, so don’t lose them.

Preparing for Reassembly

You have completed the tear-down. Now send the heads to the shop to be reconditioned. While they’re at the shop, go to the auto parts store and pick up a gasket kit for a valve job, cheap oil and filter, one gallon of anti-freeze, a can of gasket remover, one tube of Black RTV silicone gasket maker, one tube of Red RTV, and a new thermostat. While you are waiting for the heads to come back from the shop, clean off all the mating surfaces with gasket cleaner, being careful not to gouge any of the surfaces. Clean up the valve covers and the two intake manifolds with Easy-Off Oven Cleaner. Spray it on the surface of the part, set the part in the sun for a few hours, and then wash the part off. The Easy-Off dissolves the grease and oil.

Here are a few things the manual does not tell you.

  • Make sure you use quality gaskets. This whole hassle is caused by the cheap gasket GM used when they originally put this engine together.
  • Your push rods are two different lengths: the short push rods are for the intake valves and the long push rods are for the exhaust valves. If you mix these up, your heads will be destroyed.
  • While you’re waiting for the heads to come back from the shop, cover the opening to the engine with shop rags or a plastic garbage bag. Any debris—leaves, dirt, acorns, pine needles—that gets into the engine will reduce the life of your engine considerably.
  • Remember to reinstall the lifter guide plates before you reinstall the lower intake manifold.
The heads.  Don't forget to reinstall the plastic lifter guides. The coil pack installation post can be seen on the head to the right.

The heads. Don't forget to reinstall the plastic lifter guides. The coil pack installation post can be seen on the head to the right.

Reassembly of the Chevy 3.1-L Engine

Putting the pieces back together should not be a problem since you took it apart and took pictures. just take your time and be patient. Follow the manual carefully. Reinstall the parts in the reverse order that you took them out. The black RTV is used on the front and rear mating surface of the engine block; also, put a little bead of black RTV around the water jacket openings. The red RTV is used on the thermostat gasket. Once everything is bolted back on and the electrical connections are made, refill the engine with fluids. You might want to use the same coolant you drained from the engine; just top it off if you need to from the gallon bottle you bought. Start the car and check for leaks.

If everything checks out, take the car to a quick-lube shop and have them replace the cheap oil and filter with a good grade of oil and a good filter. Also, have the shop drain and replace the old coolant. I recommend paying someone else to change the oil and coolant because of the disposal issue. Trying to get a place to dispose of contaminated oil and coolant is difficult. Save yourself the hassle and have the quick lube place do it for you. They might even take the original contaminated oil off your hands, ask them—all they can do is say no.

When this project is completed, you will have successfully rebuilt the top end of your engine yourself, and you will know the job was done right because you did it. Try to fix it yourself first before you call in a professional. The worst you can do is break it some more, and if you succeed, you will save a lot of money.

A word of caution: This article is meant as a reference only. Follow not all the safety procedures as well as the repair procedures. For example, never get under a car without using a jack stand, and never open the radiator cap of a hot engine.

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.


Ken on January 18, 2016:

You should label your rockers one by one in a zip lock bag each is unique - to the cylinder intake/exhaust. ALWAYS keep same with same when doing these things.

William Green (author) from USA on January 12, 2013:

DCook, your friend is right. Whether it is a cracked piston or worn rings. IT is a difficult job for the DIYer. The reason being. IF you pull the piston and change it or re-ing it you need to change the bearings on the rod cap lower and upper. The lower cap is easy just take out the old one and replace with the new one. The upper cap bearing has to be rolled out because you have the crankshaft blocking direct access. I have never done this procedure before, but I have read about it. IT seems straight forward; however working on cars is never straight forward when it is your first time doing a new procedure. What you need to consider:

1. read everything you can on re-ring or re-placing a piston.

2. If you do one piston do you need to do all the pistons.

3. Do you want to pull the engine or leave it in to do the job

4. Est the time to do the job then double it.

5. cost vs time off the road is this your primary car or a project car.

Good luck


DCooke on January 12, 2013:

William, thanks for the information. I did find a broken lifter in the very far left corner facing the firewall. A fellow that has rebuilt a number of chevy 3.1 L engines said the camshaft may have to be replaced or even a piston may be broken. He said to take out spark plug out at that corner and pump air into ito it at around 80 psi. If normal hissing is heard then piston is okay but if big whooshing sound then ring and/or piston is probably shot. Any ideas?

William Green (author) from USA on December 23, 2012:

John you need to buy a torq wrench in inches not foot pound. hope this helps

William Green (author) from USA on December 23, 2012:

DCook at 150k miles I would take the heads off and have them done replace all the gasket.

John4 on December 19, 2012:

I just did the head gasket job on my lumina

How do you adjust the lifters

The book says to torque to 14# but I don't have a torque wrench that goes that low

Thanks for the thread it was very helpful

DCooke on November 28, 2012:

I am about ready to take apart my 3.1 engine on a 1993 Lumina auto. I know it is seriously leaking oil. Will the heads have to be removed since it has a little over 150,000 miles on the engine.? What other parts could be leaking oil besides intake and exhaust gaskets, upper manifold gaskets, and valve cover gaskets?

William Green (author) from USA on October 12, 2012:

Hi Paul, I did not place grease under the module. I do not remember if the manual said to or not. If the manual calls for grease than I would do it.

Paul on October 12, 2012:

Hey William, I too have the 3.1 litre in 2000 Malibu. Question: Did you place grease under the ignition module when you removed/re-installed? My Malibu manual says to do it for the 2.4 litre engine, but says nothing about whether to do it for 3.1 litre.

Thank you in advance.

darrell on October 11, 2012:

just had this happen to me today, feeling kinda scared to do this, i am very mechanical but kinda intimidated to do the job, going to find a manual for 95 lumina

Jay Sanderson on June 11, 2012:

Update on my project,

job went without any big issues, did it on a very casual basis over a few days (longer wait time for head bolts to arrive) spent about 3-4 hrs over 3 days in 95°f garage. heads were surfaced and checked, they were not warped much but worth the extra time and $ (only $50 for re-surface) engine was loud at first start up and had a "bad bearing" type growl sound and lifter noise, it all cleared up after worm up and has not showed up again, the noise may have been a heat shield vibrating?? the engine now runs smooth and strong, I never drove this car before repair, it's a little hot rod in a light weight 2 door Grand Am!

Please note, my research showed that torque specs in most manuals are incorect IF you are using newer/updated gaskets.

* if you use old (lower torque) values with newer type lower intake gaskets that have metal crush sleeves you run the risk of same intake leak,

*also on head bolts, there is a higher torque value that dealers and updated technicians use when doing this job (with new bolts)

William Green (author) from USA on May 27, 2012:

I'm not familiar with the 94 3.1 but it sounds like the intake gasket is leaking coolant into the oil. If that is the case you will have to replace the gaskets. To put your mind at ease you can take the car to a shop and have them check it out. You will pay for the estimate but at least your concerns will be eased.

good luck.

denlp on May 27, 2012:

have 1994 cutlass supreme convertible with 3.1, low coolant lite on today. about a gal low, checked oil dipstick and oil very runny, checked filler cap and milky. What should I do? Help!!

William Green (author) from USA on May 26, 2012:

Jay, If you still have the original head bolts, look at the markings on the top and compare them to the chart in the repair manual. That should give you the torq amount. If the number is somewhere in between 37 and 44 I would use it. It is up to you. good luck

Jay Sanderson on May 22, 2012:


it's more the torque amount I'm worried about, 44 or 37 lbs tq.

William Green (author) from USA on May 22, 2012:

Jay, I don't know the revised seq for the 1998 3.1; but when in doubt, start in the middle and criss cross your seq outward. If possible do not use the old head bolts. Wait for the new bolts if you can.

Thanks again for the support.

Jay Sanderson on May 21, 2012:

For the miles most these cars have and not always knowing how hot they got, the heads just make sense to do (if you can). But for a shop trying to sell the additional shop hours ...could be tough no matter the circumstances.

on, "...huge potentential of a major engine failure if not re-assembelled proper. I've seen the after math, not good"

the biggest possible DIY problem is keeping push rods in correct place, that needs to be done, heads pulled or not, sure there is more work and potential for problems but if you are capable of getting this far??


do you (or anyone) know if the revised head torque specs apply to 1998 3.1L?


above online revised value is 44 ft lb tq + 95° and a little different sequence patern compared to service manual at 37 ft lb tq + 90°

-I would think this is due to better gaskets designs of today & maybe different design head bolts?? but that's not stated. I'm waiting on new bolts coming from local parts store but if they don't get here soon I may just use old ones, I'm leaning towards 37 ft lbs tq + 90° if I have to use old bolts.


William, more people like you taking time sharing & encouraging is what we need.


William Green (author) from USA on May 21, 2012:

Jay, thanks for the positive feedback.

My typo's bother me than the negative comments.

Jay Sanderson on May 20, 2012:

remember, there are many more honest techs out there then ones overselling. recommending to do the heads is just good sense for helping someone or (if you run a business) to avoid comebacks, we make the decision based on source. If its a shop you you don't trust, get another opinion

William Green (author) from USA on May 20, 2012:

Wayne, When I had teeh Techs do the job it failed after 6 month. When I did teeh job I sent the heads out to be mag flux and guess what they were warpped. Aluminum heads have a nasty habit of warpping with very little over heating. I

Wayne on May 20, 2012:

I have been a tech for over 20 years, doing head gaskets for a intake leak is over kill. I've done a lot of these and never had a problem. This is a OVER SELL and there is huge potentential of a major engine failure if not re-assembelled proper. (I've seen the after math, not good)

Jay Sanderson on May 13, 2012:

Thanks for reply! I just ordered the full head gasket kit from Amazon, found local shop to resurface heads for $50 for pair, sounds low?? maybe they will get me with some disassembly charge. the compression test was185-195 psi in all cylinders

William Green (author) from USA on May 13, 2012:


IF you have been running the car for any length of time than your heads are warped. which means replacing the gaskeyt will not solve the problem. The milky oil means the gaskets are leaking into the oil and out of mating surfaces of the heads and the block.

If you are planning on selling it just take it to a dealership as a trade. Don't waste the money during the job halfway. It will start leaking shortly after you finish the job.

Jay Sanderson on May 11, 2012:

Great write up & feed back, I have a 96 Grand Am with a (written in paint pen on intake) 98 Olds Achiva 3.1L, it looks all the same as yours and others. it has the milk shake oil and low coolant, she said it was not over heated and stopped using as soon as oil slop was seen, Question, water was added over a few days and I assume the crankcase is way over full with the oil/water mix, but there was a good size puddle of oil under car, I can't tell from where yet. is this blow by from overfill or is it likely something something else is up?

I'm doing compression check tomorrow. if it checks out Okay (what should I expect?) I plan on just doing the the intake and sell it after, if I was going to keep, I would do the heads completely with new bolts. the part # for just the intake kit upper & lower from Felpro is #ms90562 (its supposed to have spacers at bolt holes to prevent deformation compared to previous designs) available on Amazon or oreilys for about $50. ....the complete head gasket kit is felpro #hs9957pt2 for about $160. is this a wise move? I can hardly afford anything on this car but i need to at least get it running now. Thanks in Advance!

Jim on April 28, 2012:

I tried to remove the valve springs to get the pushrods out just like you said.... That dont work so I went back to the way we did things 35 years ago and removed the ROCKER ARMS so I could get the pushrods out...Then I tanked them clean, changed the stem seals,( maybe this is where the valve springs have to be removed ) checked for straightness and wah-lah back together. Still a piece of crap engine and most of the cars left with it are not worth the price of gaskets and bolt kits

William Green (author) from USA on April 16, 2012:

Hi DarkFlame,

If I can help I will. What do you need?

DarkFlame on April 14, 2012:

Hi are you still helping people out?

William Green (author) from USA on March 30, 2012:

Rooster I do apologize for missing your comment. The new coolant looks a lot like transmission fluid. It could be a gasket problem. Before you go tearing the engine apart I would strongly urge you to get it check by the dealer. Paying a diagnostic fee will be the best money you will spend. It could be a simple fix. You will still save money when you do the repairs yourself. Goodluck.

rooster29 on February 20, 2012:

i have a 2003 chevy malibu and clear oil and oil cap, but i am adding coolant to it about once every 1000 miles and i do have some what appears to be transmisson fluid in my reservior and have that white substance on the cap of it time to time..is this transmission cooler issue or one of my gaskets?

William Green (author) from USA on February 20, 2012:

Brian, the water jets (ports) are on the end of each head. (2 per head) just use the RTV on that section of the gasket. You do not need a lot just smear a little RTV on the small rubber portion of the lower Intake gasket which meets with the water ports.

I'm not farmiliar with the gasket sets you mention so I'm afraid that I can't help you with that. However, if some post a comment concerning those gaskets I will get it up on line quickly.

BrianRamey on February 19, 2012:

So far this thread has helped me as much as the Hayne's Manual. I used hyour shopping list and got the felpro performance gasket set from Advance Auto. The whole set, HST9957-PT2 lists for $235, but by buying the intake set and other gaskets individually, I was able to get everything on the list for about $165. I used code CCABIN, which is $10 off of $30, $20 off of $50, and $40 off of one hundred. I made two 100 dollar orders and a 30 dollar order and saved $90. Yay!

Question: The lower intake gasket set (MS 98004 T, with permadry plus gaskets) comes with instructions to use the black RTV on the front and rear. I'm assuming that's the flat part against the block that doesn't have a gasket. The instructions said the sealer cannot be used on the "side rails". What is that? You said put RTV around the water jets. You didn't mention the air intake ports? What is the side rail? The lower intake gaskets look like black rubber on a metal frame.

William Green (author) from USA on February 19, 2012:


On my engine the short push rods are for the intake valves and the long push rods are for the exhaust valves.

Did you keep them in order when you took them out?

Steve on February 18, 2012:

Im changing intake manifold gasket and need to know which pushrod bolt goes to the exhaust long or short on a 3.1liter

BrianRamey on February 17, 2012:

Wow, 2 years and you are still helping out. Perhaps you could help me?

My wife drives a 1995 Buick Regal with a 2 year old used engine. Last year she had a head gasket leak, and her ex husband changed out both head gaskets (I wasn't available, and he went to mechanic school). We've had missing coolant and skipping getting worse recently. A code scan showed cylinder 2 missing. Today I pulled all the spark plugs, pressurized the radiator for 2 hours at 16psi, blocked the plug holes with paper towels and turned over the engine. Water came out of cylinders 1 and 2 onto the paper towels. So I am assuming both head gaskets are leaking? Could it be the lower intake manifold?

I'm planning on pulling both heads tomorrow and taking them to the shop. Since it seems both gaskets failed, I'm planning on buying new bolts, chasing the threads in the bolt holes, and trying to clean them out with brake cleaner and compressed air from keyboard cleaner.

I saw you used Felpro gaskets. Advance has a set for 140-160 depending on valve seals, and a 'performance' set for a whopping $250. Will the regular gaskets work? Also, what about the copper permatex sealant? Would you use that on the head gaskets? If so, spray or tube?

Also, I notice a lot of people asking about missing coolant. Don't forget the 2 bleed valves for the radiator (top of thermostat driver's side and heater hose junction on passenger side).

Thank you for writing this article. I didn't know if the steering pump was going to have to come off or not. I already have the alternator and coils off.

William Green (author) from USA on February 15, 2012:

malibu, those are signs of a major gasket leak. You need to replace the lower intake gasket You should also take off the heads and send them out to be resurfaced.

good luck

malibu on February 14, 2012:

Quick Question. I have the water/oil goop in the valve covers, but not on the dipstick. I hear a tapping (which everyone considers normal) on startup. Is there any recommendation you can give me to reduce the ticking? Also. What is the best way to do an "engine flush" to clean out the junk oil?

William Green (author) from USA on February 14, 2012:

CJ, did you send the heads out to be resurfaced? The heads might have been wrapped so when you put them back on it would not matter how tight you did the bolts. Did you replace all the head bolts and lower manifold bolts? this can also cause a problem.

CJ on February 14, 2012:

Well we just did my intake gasket on my 99 grand am gt 3.4 and all was fine until about a week later it started idleing rough and got a random p0300 and then it switched to a p0302 code. Ive got coolant in spark plug 2 and its causeing missfires when running. I stopped using the car as of the moment but im trying to figure out what it could be. We made sure it was torqued correctly and rtv'd everything we had to.I am trying to find ways to figure out what the problem so i dont have to have a wasted gasket set on my hands when i pull it apart again.

William Green (author) from USA on February 12, 2012:

That is great Annie.

Maybe the gas cap is not screwed on tight. Same thing happened to me. tighten it down until the click then erase the trouble code.

William Green (author) from USA on February 12, 2012:

Andy, the manual, for a 1998 and later (3.1 liter), give the tighten sequences as a two step process.

Step 1 tighten to 168 inch -lbs

step two tighten an additional 30 degrees. DON'T tighten to 168 Foot lbs.

William Green (author) from USA on February 12, 2012:

Ryan, If the fluid is coming out the rear cylinder bank than it is a gasket problem.

annie on February 11, 2012:

it's leak free now, thankfully! i just have one more question... my service engine light came on recently. i got it scanned at auto zone, said new fuel cap. bought that, light is still on. what could this be?

ANDY on February 09, 2012:

is there a specific ft lb for the push rods?

Ryan on February 08, 2012:

I have the 3.1 in my 98 monte ls. I parked it one day and it leaked a whole bunch of coolant on my driveway. I've been watching it for a few days, and it does not leak while running, but when I shut it off, it leaks a decent amount.

Today, I parked it in my flat garage, shut it off, and shook it back and forth, side to side, and up and down, and I had 4 decent drip spots on the floor of my garage. I took a flashlight and looked down the rear driver's side of the engine, right below the head, and behind the throttle body. It looks like there is fluid running down the back of the engine. What is this? Can you help me? Is this the gasket, or the manifold?

annie on February 07, 2012:

I filled the line up to cold and within 2-3 days now the whole res will be empty... but there is no leak on the ground anywhere in sight, and if you run it for 20 or so minutes and watch it you still will see nothing leaking. It's not leaking into my oil pan (yay!) so the guy who's been doing work on it said it might be the thermostat?? He only had a few minutes to look at it today as I had to go to work, however, so he hasn't done a full inspection of it. It's just weird because there is no coolant in sight anywhere under the hood and it's not coming out under the car and it's not going into the oil. I'm just wondering where the heck it's disappearing to, it's like it's evaporating.

Thank you so much for your help so far!

William Green (author) from USA on February 04, 2012:

Annie are you sure you put enough coolant in the system. Before you do anything else double check the fluid level. Fill the res up to the line for cold. Run the engine if the res is empty try it one more time. If the res has fluid than you should be ok. If it is empty then you have another leak most likely the radiator. Good luck

annie on February 03, 2012:

Hi. I got the water pump replaced, but the reservoir just went empty again so apparently it is still leaking from somewhere. :( It doesn't look wet inside at all (which it did before gasket/water pump replacement) so I'm wondering if maybe this time it's the radiator?? Ugh! Cars!

William Green (author) from USA on January 29, 2012:

Just Kris,

Good mechanics at reasonable rates are getting harder and harder to find. I am glad you have one stick with him.

Just Kris on January 28, 2012:

I have a '98 Chevy Lumina and was dealing with overheating. That the radiator cap replaced and the thermostat. Had the air bled out and it ran fine for a couple of days. Overheated again and had the intake manifold replaced. Ran fine again for a few months and started overheating again. This time it was the water pump. No issues for about 6 months and then the car just shut off while I was driving. Fuel pump was just replaced. Thankfully I have a mechanic who guarantees his diagnosis and charges me a fraction of taking it to a dealer.

William Green (author) from USA on January 27, 2012:

Your friend is right it is the water pump

annie on January 25, 2012:

Also might I add I have a 1996 Chevy Lumina, 3.1V6 :)

annie on January 25, 2012:

I just had by upper & intake manifold gaskets replaced by a trusted friend who's been working on cars for years. The car runs much better, but is still leaking a whole reservoir of coolant a day. He says it's the water pump; backing it up is that the coolant puddle under the car is always only on the side of the water pump. Also, the engine only looks wet around where the water pump is instead of being completely soaked before the gasket replacement.

Would a failing water pump still cause such a bad leak, however (I assume it's been failing for a while, I've been fighting coolant problems on this car for years). I'm terrified that it might be my radiator.

johnnie on January 24, 2012:

I have a 97' lumina (3100), and have been running into some overheating problems(mind you it's winter). A friend replaced the thermastat and bled the air out of the system, but still runs through coolant every 2 days and still overheats. I been reading alittle on the net about blown head gaskets and a few other things(including "steel seal") and still not sure what I should do yet. The car starts to overheat within the first 2 miles, engine hot light goes on for about 1-2 miles, then starts cooling itself again like its fine. Before I do anything, I would like to hear your input on the subject. I would greatly appreciate it. ty

Dave on January 24, 2012:

I have a 1996 lumina and need help diagnosing. It died and won't stay running just backfires thru the intake. It's getting spArk and fuel.

William Green (author) from USA on January 15, 2012:


Sorry it took so long to get back to you, Work and life have kept me busy. It would not surprise me about the gauge flaw. However, I have never had that problem. Changing a sensor is pretty striaght forward just find it and unscrew it. Wrap the threads of the new gauge with teflon tape and put it in. Connect the wire connection and you should be all set. The only problem I foresee is loss of oil depending were the gauge is located. Sorry I can be of more help. Good luck

thump1st on January 09, 2012:

here's a question. How do I Replace the oil pressure sensor? My gauge is fully open a long with my fuel gauge & from what I've read if the oil pressure sensor has shorted out it'll affect the fuel gauge (gm design flaw).

William Green (author) from USA on January 07, 2012:

Dan, The knock could be from damaged main bearings, piston rod bearings, cam bearings, or lifters. What does the knock sound like. Is it a deep pitch or a high pitch knock? A deep pitch knock mostly likely means main bearings. A higher pitch knock could be cam bearings or lifters. No matter where the knock is coming from it sounds like bad bearings. If this is not fixed you will have an engine failure. You said your niece ran the engine without any oil in the pan. That will cause the bearings burn. You need to check all the bearings. That means a complete tear down. You will have to decided which is cheaper buying a used engine or fixing the one in the car. Good Luck

thump1st on December 25, 2011:

I'm officially signed in (I'm Damien aka), thump1st. I went 2autozone, got that assorted o ring set. Put it on the end of that fuel rail. runs lovely now! Just need 2power clean that motor. Thank you William

William Green (author) from USA on December 24, 2011:

Damien, The same thing happened to me. You either forgot the o ring orthe o ring is bad. It is an easy fix. Good luck

Damien on December 23, 2011:

I put everything back 2gether. When I turn the key 2start her up the fuel pump activates and fuel comes spewing out the fuel rail @ the connector line. Is there a gasket that I missed that was supposed 2go on the end of the hose? Or bad o ring(s)?

William Green (author) from USA on December 06, 2011:

Chevy 02 malibu. If this is your first time, you should plan on a day or two to do the job. Take your time do not rush. Good luck

Ruben D. on December 06, 2011:

what car was your set up on.. i just kinda skimmed. i'm about to tackle a 3.1 on a 01' lumina (sedan). man i hope it as easy as this makes it out to be i can probably knock it out in a few hours. but i forgot about the draining fluids bit. damn, i have to wait till next week.

Andras on November 13, 2011:

Thank you for the useful writeup, very informative!

I bought my '95 Chevy Lumina sedan 3.1l from an old lady, who was the original owner of the vehicle. I don't know if the intake manifold gasket was replaced or not, what is the mileage that they usually fail? I have 110k miles on it. Also, do valve stem seals known to fail at this mileage? My car uses about a qt of oil every 500 miles, no smoke though, only the smell. I did a compression test and read out between 180-200 psi. The spark plugs get this white powdery build-up- what led me to believe that my valve seals are leaking. I check and clean them about every 2000 miles. Any info is greatly appreciated!

William Green (author) from USA on October 20, 2011:

It could be a cracked head. Did you have the heads checked before you put them back on the block. Aluminum heads can crack due to slight overheating compared to cast iron heads.

Eric on October 20, 2011:

Great Hub!. I did this job myself on a 3.4L, same steps. Got a problem now after 2 days of driving. It is overheating and smoking antifreeze. There were no leaks detected after the repair,and the coolant level has not dropped. What am I missing? I'm afraid it may be the block....Any thoughts?

drew on September 18, 2011:

I have a 97 skylark 3.1

genadian from USA on September 15, 2011:

I just did this on a 2002 Grand Prix. It started out with just A fuel injecter. I decided I would replace all of them. When I tried to remove the injecters from the lower intake the plastic tips popped off and went down into the lower intake. I pulled the lower intake to get the pieces out. I saw that the rods had to be pulled to replace the gaskets. I cleaned everything up and installed new gaskets. The only problem I found is after putting it all back together is the upper intake is leaking and is probably warped. I will replace it soon. The car runs great. I did not remove the heads as this engine is over 220,000 miles. I will be looking for a replacement to rebuild soon anyway. I did use cheap oil and filter for 2 days then changed the oil with good stuff. I flushed the coolant and washed the resevoir bottle as well. alot people tend to overlook that. Very good article. I did not have to jack the engine to remove the engine mount as it was not in the way. The front dampener or dogbone was.



William Green (author) from USA on September 03, 2011:

Hi TJ, since the oil was contaminated by the coolant, your camshaft was not being lub'd and the stress and over heating most likely cuased the Cam to fail (break)

William Green (author) from USA on September 03, 2011:

James if there is coolant in the oil and fluid is coming out f the intake gasket than your lower intake gasket is leaking. Sorry for the bad news.

james on September 03, 2011:

Hi william i have a 95 lumina and there is no coollant in the cylinders but coolant is coming out the intake and its in the oil do you think its the intake gasket

Please help me out

TJ on August 30, 2011:

I just had my head gaskets replaced as well as the intake gaskets. I was driving down the road and my 98 lumina died. I took it to a different mech. He said the cam shaft was broken. Anyone ever heard of this? Thanks TJ

JTW Jr on August 29, 2011:

Just replaced the lower intake gasket on mine this weekend. Took me roughly 6 hours start to finish. Hardest part was indeed the rear lower valve cover gasket bolt. While I was in there I did install new plugs , much easier with the coil pack out of the way. I did not however remove the heads. Machine work in this town is ridiculous , when I did the 4 cylinder in my wifes Contour , machine work on the head cost $300. Car is now running fine , though I think we should each get a free whack at the Chevy Engineers for designing a intake gasket that requires you to remove some of the pushrods. What a poor design.

William Green (author) from USA on July 25, 2011:

Thanks Doug, I replaced all the lifter. Since I was that deep into it, I felt I might as well spend the extra money and not have to do it again.

doug richards on July 25, 2011:

good article have done intake as well didn't have to pull any mount bolts (90 Cavalier) miserable job but went well make sure you have a good look at lifters I had a 4 that were "popped" replaced 3 ( ihad only bought 3) should have done 4 repaired 1 (cause didn't have a replacement

fashion on July 23, 2011:

Informative article.......

William Green (author) from USA on July 08, 2011:

Thank you Brent

Brent on July 07, 2011:

No need to remove the mount to access power steering bolt. Use a short 15mm socket, swivel, short (about 3-4") extension and ratchet. Remove the one mount bolt in the way and save a ton of time. This is why folks pay me.

William Green (author) from USA on June 06, 2011:

Dave you might have wrapped heads or cracked head. If you take the head have have it checked.

Dave B on June 04, 2011:

You're right. (Un?)fortunately I will not be at their mercy as I try to fix a wicked coolant leak around the water pump. I changed the water pump twice now thinking I had a bad water pump. Runs cools as heck, except it is leaking :(. The only place I could figure it is leaking is at the head on cylinder 2 (the one left front). I am learning a lot but it's getting hard to be patient or have confidence.

William Green (author) from USA on May 19, 2011:

Good Job Dave B. You will never be at the mercy of the dealership mechanics again. I'm glad this helped.

Thank you for the compliment.

Dave B on May 19, 2011:

Really appreciate the post William. It gave me the confidence to get in and do it for a 99 Lumina. The way you put it sounded just like my reasons to NOT do it, but I did with your help. It was not 'easy', took me 3 vacation days off work 2 weekends and 12 nights to do it but it runs wonderfully now. The only caveats I would put out there for anyone else are to be aware that a valve pushrod might jiggle out of place when you first start the engine. I was afraid that my 'help' put them in the wrong way and destroyed my engine. I re-mounted them and purred perfectly upon startup.

William Green (author) from USA on April 16, 2011:

WHen you took the heads off did you send them to the shop to be checked for cracks and warpage.

If you bought a junk yard motor did you pull the heads and have them checked at the shop.

Pandaman on April 15, 2011:

I have replaced the head and head gaskets but I still an over heating problem, and the oil and water is mixing in the radiator and oil. I have replaced the lower intake gasket at least 5 times and I still have this problem even after changing motors. Can anyone tell me what I'm doing wrong or what it could be?

Bob on April 11, 2011:

I removed my heads on my 3100 installed new gastets head and intake. When I put the eng back together it started but only ran for about 4 mins and shut down. I took a compressoin test and found 0 to 30 lbs compressoin. I can not ajust the valves so I removed the heads and had the shop check to see just how much they milled off. They said it was only 1,000 over the minumin. I am going to install head shims. I hope this takes care of my low compression. HAs any one else had this happen?

William Green (author) from USA on April 08, 2011:


If it is a Buick it is similar that is GM. Mercs are Fords different company different design, different procedures. Read your manual carefully.


wes on April 07, 2011:

ok bill so i lied...its a buick. But regardless, have a good idea from your info, thanks and ill let you know how it goes!!!!!!

wes on April 07, 2011:

thanks Bill...its actually on a mercury sable 3.0 6cyl. is that kind of the same setup as the 3100? i mean im very mechanically inclined just not so in depth as this will be. i know i can do it....like you said...label,bag and pics.

William Green (author) from USA on April 07, 2011:


Just take your time. When you get tired and frustrated stop for the day. DON'T over tq the Upper Intake Manifold bolts. Label everything and take clear pictures. Bag everything.

Folow the shop manual and you should do fine.

Good luck let me know how it turns out.


wes on April 07, 2011:

im fixin to replace the LIM gasket and have never done it before! after reading through this post...i feel real comfortable. is there any other insight or info for a "newby" getting ready to tackle this task? thank you!!!

stereos on March 12, 2011:

it was interesting.

William Green (author) from USA on February 26, 2011:

Hi Scott,

What side of the engine are you looking from pass. or drivers. If it is pass side than it is the AIR solenoid valve, or the AIR Check Valve. If you are looking from the drives side than it would be the Manifold absolute pressure sensor ( under the coil pack) or the EGR valve. Your manual should help you out iD ing the sensor.

I would check your PCV connections it sounds like their might be a bad connection and the system is not properly sealed. That happened to me. As soon as I fix the connection the engine ran fine.

Hope this helps


Scott on February 25, 2011:

Hi Will,

Can you please tell me what that sensor is, right above the left valve cover bolt??? I replaced intake manifold gasket the other day, and now engine surges and engine light is on?? Think I might have forgotten to plug a sensor back in. Got a 98 Malibu 3.1. Dont know what else it could be. Any info would be greatly appreciated!!

William Green (author) from USA on February 22, 2011:

Scott, thanks for the compliment.

Scott on February 21, 2011:

Wow, I just did this job today before reading this article. Everything you mention was dead on accurate. Excellent article!!! A+++

William Green (author) from USA on February 11, 2011:

So far so good no bearing problems.

big blue on February 11, 2011:

yeah, i think i'm just going to do that instead. But i heard that the antifreeze might mess up the main bearings, and that they eventually will go out, somewhere around 50,000 miles. so, how has your car ran?

William Green (author) from USA on February 11, 2011:

Big blue,

Dropping the pan and cleaning the oil pump would be an easy job, I had a foamy mixture that was coffee colored. I didn't drop the pan, but I flush the engine three times with cheap oil and cheap filters. I did not want to get into replacing the pan gasket and monkey around with the oilpump. I was outside and didn't want to risk getting dirt into the crank case. If I had access to a garage I would have dropped the pan and changed the pump.

I ran the engine about ten minutes each time.By the third flush, the oil was coming out as if it was right out of the bottle.

big blue on February 10, 2011:

I have a question, how much of the substance did you find in your car? because the car we are fixing had a lot of the antifreeze/oil mixture in the engine. So do think i should take out the oil pan to make sure the oil pump doesn't plug, or how should i do an interior clean?

thanks for your time

William Green (author) from USA on February 02, 2011:

Doug, I'm glad this helped.

Thanks for the response.

Doug Caple on February 02, 2011:

thanks for the insight...makes the job easy cause you are clear and also some short cuts...my tear down was only 4 hours...and the kit was 100 bucks ...the dealer wanted 1200...plus

I am now replacing the gaskets...thanks again

Related Articles