How to Replace Intake Manifold GM 3800 3.8L: Pontiac Bonneville, Buick LeSabre, Pontiac Grand Prix etc..
The upper intake manifold is a very common failure point on the venerable GM 3800 Series II Engine. Often when it begins to fail, the car will show the symptoms of a head gasket failure, however actual head gaskets failing on this engine is VERY rare. One of the first signs of the intake manifold failure is coolant loss, these intakes can leak internally into the engine, or externally near the thermostat housing. In extreme cases, the leak can get so bad internally that it can actually Hydrolock (when an engine fills with so much liquid that the pistons cannot move up in their bore). This was the case on the example car I will show you today.In the case shown below, the owner of the car thought the head gaskets were bad, and it would need major repair or a new engine. After a quick inspection I knew it was only the intake manifold that was bad. The car had stalled on him, and would not turn over at all, acting like the engine was seized.
Before I start, here are the exact vehicles affected by this leak:
95 96 97 98 99 00 01 02 03 04 05 Pontiac Bonnville 3.8L
98 99 00 01 02 03 04 05 Chevy Monte Carlo 3.8L
00 01 02 03 04 05 Chevy Impala 3.8L
96 97 98 99 00 01 02 03 04 05 Buick Lesabre 3.8L
96 97 98 99 00 01 02 03 04 Buick Regal 3.8L
95 96 97 98 99 00 01 02 03 04 05 Buick Park Avenue 3.8L
95 96 97 98 99 Oldsmobile Delta 88 3.8L
96 97 98 99 Oldsmobile LSS 3.8L
All 3.8L (3800) engines with VIN code K (8th digit of VIN) Non-supercharged
Before you tear into it, there are two important steps,
1) DISCONNECT the negative battery terminal
2) Drain any engine coolant that may still be in the car (there is a small drain near the bottom of the radiator). After these two steps, you must gain access to the intake manifold by removing some things that are in your way.
3) Remove the engine cover by turning the oil cap to loosen, then without pulling it off, continue to twist it counterclockwise, when it stops completely, pull the oil cap AND oil cap tube away from the engine. You can then lift the engine cover off of the engine.
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3b)
Remove the air filter housing. Loosen the two philips screws on the housing itself, then pull the throttle body hose end off. (Peel back the top of the hose, then work around until the whole thing comes loose) Disconnect the plug going into the intake hose, and remove whole assembly from car.
4) If the spark plug wires aren’t marked, mark which one goes where on the coil pack, and pull the three plug wires that run to the rear off of the coil, and let them fall to the rear of the engine bay.
5) Remove serpentine belt.
6) Loosen the three alternator bolts and remove wiring from back of alternator. Remove alternator and set aside. NOTE: To remove one of the bolts, you must remove a bracket which runs from the Alternator to just below the Ignition coils.TIP: There is a bolt which is hard to see just below the belt idler pulley.
7) Remove the 6 Fuel Injector electrical plugs, (Squeeze in on the metal locks and pull up) Remove the three electrical connectors going to the throttle body. Remove the electrical connector going to the MAP sensor (sits on top of the intake manifold near the alternator)
Remove all vacuum lines going to the throttle body and intake manifold.
9) Remove the fuel lines from the fuel rail. You will see two plastic lines going the the fuel rail, they are both held in by small plastic clips. To remove them, squeeze in on the bottom of the clips, then pull up on the fuel line. **CAUTION** There may be some residual fuel pressure in one of the lines, so remove the lines very slowly and carefully.
10) Remove Fuel Rail with injectors. There are four nuts which keep the fuel rail, and injectors in place. Once you remove those four 10mm nuts, carefully wiggle and pull upwards on the fuel rail, and the injectors will unseat themselves from the lower intake manifold, and the whole fuel rail will come out. Set aside.
11) Remove Throttle Body. There is a bracket which connects the throttle body to the cylinder head, this little bracket blocks access to one of the throttle body nuts. My trick is to remove the Bracket-to-throttle body bolt, then carefully pry the bracket back until you have enough access to reach the nut with a deep 10mm socket and extension. You can leave the throttle cables attached to the throttle body, and just position the entire assembly aside.At this point, you should have clear access to the entire upper intake manifold.
12) Remove all of the upper intake manifold bolts, and remove the intake from the car. If the intake does not want to separate from the lower, then you most likely missed a bolt. it should NOT require any prying to get it loose.
13)Now if the intake was leaking internally badly, you will likely see an alarmingly large puddle of coolant sitting inside the engine. It is CRUCIAL that you remove all of this coolant, use Paper towels or old rags to soak it all up. Clean the gasket mating surface on the lower intake manifold.TIP: It is very important to have a clean mating surface on the top of the lower intake manifold, or you may encounter leaks.
14) Snap the upper intake gasket into place onto the bottom of the new upper intake manifold and place the upper intake back onto the car, make sure all the bolt holes are aligned.
15) Install and tighten all the bolts in the following sequenceNOTE: The Specified Torque is ONLY 89 INCH pounds,, which is less than 10 ft. pounds.. be very careful not to overtorque and risk cracking the new intake.
16) Reinstall all accessories and wiring, and fuel rail in the reverse order of removal. Refill the coolant system.
17) IMPORTANT STEP: If you saw ANY coolant at all inside the intake manifold upon removal,, you MUST replace the spark plugs. Also it is very important that you remove most of the coolant that may have entered the combustion chambers. Which is simple to do
17a) Remove all six spark plugs, and turn the engine over (pretend you’re starting it) for at least 30 seconds. Install six new spark plugs and you are good to go.
18) Start car and let idle for a while, check for any coolant leaks, carefully watch your temperature gage to make sure no overheating takes place. Once everything looks good, you are done!Congratulations, you just saved yourself Hundreds of Dollars by Replacing your own Intake Manifold on a 3.8 Liter 3800 Series II Car!
Written by Joe S.
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Thank you for this information. My sons 2002 Pontiac Grand Prix is a GTP with supercharger. Is it much more difficult when supercharge is on top of intake? If you have additional information on this replacement, would you eamil me. I read and artical that the GM on pre 2000 3800 has a defect that causes over heat on egr valve. Is it recommended to replace the whole intake manifold dorman. My son will be keeping this car for several years and we want to keep in running condition for 3-4 years. Thanks JIM
thanks, saved my car. should oil be changed also?
Upon bringing my 97 Grand Prix G.T.P. to the dealership this morning (for the supercharger/fire recall) the service mgr. advised me that the mechanic found that the lower intake and the rear valve cover gasket was leaking (probally making it even easier for cooleant to get into the engine oil, right?) So, I guess my question is similiar to #1 above, but also, would you get the new manifold/kit/gaskets from the dealership or aftermarket? I’m guessing the aftermarket would be cheaper, but the service mgr. said that if they did the work, it would be guaranteed for a year, is this because they have some confidence in their work or because their parts are better? He said it would cost $1100., so I’m thinking of doing this myself. Otherwise, this car has produced 141k miles of driving excitement. Also, what aftermarket brand drivebelts would you recommend or is that also something that should be bought from the dealer due to any possible quality shortfalls?
It is easier to leave the throtttle body attached to the plenum and remove them together as one unit because of the difficulty of removing the lower nuts-Also would strongly advise to remove lower intake manifold and replace that gasket also and check the manifold for degradation cased by the infamous Dex-Cool
I just completed the change of the upper intake plenum on my ‘95 Buick Park Ave. I refered to ypu article a couple of times and I found it to have some good hints. One thing I would suggest an oil change after completing th job just to be safe. Thanks again for the info.
Thanks for the information. It was very detailed with good hints, and allowed me to repair my 1997 Buick LeSabre for about $200 (versus the $1400 the rip-off man down the street wanted). One thing I advise is you get the updated upper manifold and EGR tube. The one I bought had blue (versus orange) gasketing for the coolant seals (I assume this is a better seal for that application….my old, failed unit had orange ones in that location). Also, you want to replace the EGR tube (near the throttle body) with a smaller diameter tube (should come in the upgrade kit). This prevent the hot exhasut gas (used during warm-up) from heating and distroiting the plastic manifold, as it is not in direct contact with the manifold. The only problem I had was the tube did not fit tightly into the lower manifold, so I added some indentations with a chisel along the large diameter, which created a tight fit.
WOW! My 95 Bonneville seized up yesterday, with the “Low Coolant” light on and not much in the radiator. I was thinking the worst, but from what I have read today from several sights, this is exactly what I have. I am printing the instructions and am going to replace it tommorow, in the garrages parking lot where I had it towed, they know me, they had Better not mind… Thanks SO much for this info. Roy
Thanks Good reading !! I’m in the middle of doing mine now.
After completeing all the step up to putting the new manifold on the engine, shouldn’t I be able to turn the engine with a wrench. Before I put the new manifold back on the engine? URGENT
you probably wouldn’t be able to turn it very easiy, as you are still creating a great deal of compression in the cylinders. you are also moving the rocker arms, the valve springs are pretty strong.
If you want to turn the engine by hand (to ensure it’s not seized, etc) you can take the spark plugs out.
That way, you aren’t trying to compress the air in the cylinder that’s on the compression phase (valves closed and piston moving upwards)
I had this issue and put it back together. It seem to run fine but then it began blow smoke. I took it apart again and now I have lots of oil in the upper intake simulat to the amount of coolant last time. It seem to be comming from the same place as the coolant was. The EGR hole. I did not push that sleeve down there. should I have? Where is the oil comming from? Where can I find more answers.
Thanks,
I m loosiing coolant some where ,how do I check upper manifold lleak.
attention Joe S.
thank you so much for your detailed information about the upper intake manifold.
I kept posponing doing it, now i feel more secure thanks again.
gerard
for info I also found an interesting information about and upper plenum and lower intake repair kit at:
//ken-co-com/manifold/
I too have a GTP with a leaking intake manifold (2001 with 86.000 miles). Is there further instruction available for replacing the intake manifold on a GTP? I’d read where two others have commented that they need to repair their GTP’s also, but haven’t seen any answers concerning it. Please advise, thank you for the info already posted!
I had never heard of an engine hydo-lock until this one. Wasn’t sure what the heck was going on. I knew it was water, but not sure how so much could get in there so fast and lock up the motor. The intake makes sense. I will be tearing into this today with your printed instructions. Thank you. Steve in Oregon.
The procedure I used to replacing the upper intake manifold gasket was exactly as you described, but when I started the car and it flooded within seconds. Did I miss something? By the way, I think what you’re doing deserve great praise. Keep up the advise.
I’m repairing a car with the same problem right now. Due to the engine taking on water, I pulled the lower intake and heads for inspection. I’ve heard the hydro locking can actually bend a rod. I just cleaned everything up and checked everything and believe I have a bent rod. 5 of the 6 pistons come up .025″ above the cylinder bore, the 6th sits .035″ below. Is this motor toast? Thanks
So you want to know how to fix or keep you intake platoon from going in the can. Well, I’ll let you know what happened in my case and hope that it answers your questions.
I have a 1997 Buick LeSabre Custom with a 3800 Series II V6. I overheated on the highway and was able to make it to a local parking lot. I turned off the car and found nothing in the way of what you would typically find in this case. The radiator hoses were cold! So I opened the radiator cap and found nothing, no coolant? I allowed the car to cool and then added water to see if I could find the leak. The car started but was running rough, so I hit the throttle body to give it some gas and it stalled. I tried to start the car again, and on the second attempt the car engine just stopped. Again I looked for a leak and found nothing… Where the hell did it go? Can you say hydra-lock? After a tow home, I pulled the spark plugs and the water came out. In fear that I may have warped or cracked the heads, I began making phone calls. I was not too concerned about any real engine damage, because the car was not under a running load at the time the water filled the cylinders.
Soon it was time to start taking the engine apart and investigating the extent of damage. When I pulled off the platoon I found the top half of the intake was full of water. The gasket around the EGR stem had melted the platoon and gasket and allowed the water, I put in earlier, to be pulled into the cylinders. Now, I should say that the car had been running rough for a few days. That may very well have been the beginning sighs of the problems I was about to face. After spending some time on the net (like yourself) I did find a lot about the EGR problem melting this platoon. It’s seems to be a BIG issue with this engine and usually happens around the 100,000 mile mark,… but why? I could not find the answer. And this is why I’m taking the time to type it out.
On the water pump manifold is a little plastic elbow tube. This manifold, on my car, has the tension pulley on it as well. The coolant start to brake down the plastic over time. At about this point in the engines life, 100,000 miles, the tube starts to give and weep. Most people don’t no this, because the weeping is burned up on the engine and caught in the guards under the car. So you have no sighs of a leak, like the big pond found under the car. So by the time it is caught, it’s too later. If you haven’t had the issue to the platoon yet, check the tube or just replace it. It cost about $14.00! Also it’s a dealer part. It’s a small price to pay and you only need to remove the alternator to get to it. The manifold is a little tricky to remove. The casting part that is inserted in the pump has an O-ring. With a little faunas, it dose come right off (Don’t forget the bolts too!) The whole job should take about 2 hours if you are taking your time. If the manifold is the issue, it’s about $155.00.
With regards to the platoon, they give a an adapter to REPLACE the EGR stem. Measure the height, grab your vise-grips and twist the old one out. The new one is smaller than the old size. They give you two different sizes, depending on which one you have. The head on the replacement tube is the size you have now. They made the size smaller to create an air barrier between the plastic and the stem. Also the plastic water jackets are little thicker in this area.
When all was said and done:
Intake Platoon : $180.00
Full Ejector O-rings : $20.00
Water Manifold replacement parts : $15.00
Radiator Hoses: $45.00
Coolant: $20.00
Tow truck to the house: $100.00
Total: $380.00 + Beer to do it yourself.
Not bad for what you may have spent at a repair shop!!
I hope this story helps with your project and GOOD LUCK!
-Tony (Tool & Die Maker)
Livonia, Michigan
Great info! I took the cables off the throttle body it took a few days to find how it done but I finnaly found out. When the upper intake was remove it wss as you said it was full of coolant. My intalke does not look like it got any cracks it looks as the gasket gave up I going to try that first. But final most repair shops wanted to install a use motor since it hydro lock and one shop would tear it down but it would cost $2,500 to start! The other shops were around $1800. Thanks again.
hey wanted to say that i had already taken my upper and lower inatke gaskets off and about to replace them. however when i pulled my intake manifold off i noticed coolant and oil mixed togethor, my upper manifold was ok but i will replace it anyways and my lower manifold gaskets were just flat out no good. my question to you is how do i continue to let or make sure that their is no more water in my block causing it to not fire. now i havent put it all back togethor just yet but i have drained the radiator and the oil. if you could get back to me and let me know if theirs anything else i need to know or do before i start putting it all back togethor it would be much appreciated,,, thanks.
98 Buick Park Avenue… $1800 to replace the lower intake manifold when it failed at speed. Hydrolock occured. First shop wanted to replace the engine. After a tow to the dealer they fixed it for big cash. 70,000 miles. At 117,000 miles car is losing coolant. Changed the coolant and added stopleak. The next day a failure at speed again… thought it was a blown head gasket. No hydrolock, but rough idle and lots of white smoke. Still ignorant of this site I found a new garage who correctly diagnosed a failed upper intake manifold. $850 this time.
I’m armed and dangerous now and ready to do it myself next time this car craps out. Thanks for the great service.
I have a small leak on my 3800 just underneath the alternator. I washed the top of engine and it seems its leaking around the first bolt on the manifold by the alternator. I put some coolant dye and pressure tested the system. That’s the only spot I can see a few drops of coolant…around the bolt settling in the manifold pocket just under the bolt. Pressure los was about 5Lbs in approximately 7-8 minutes.
Oil is clean and coolant los is about 3/4 cup in the last 10 days.
My question is since there is no visible leak around the manifold gasket, is the bolt hole open into the coolant jacket and is it possible for the coolant to leak around the manifold bolt. Car is a 2001 Grand Prix with about 55K miles.
Thanks for any help
All the information is very good, I just replace the lower intake manifold on my 1999 gtp I want to know about the torque for the intake and the supercharger
I replaced the plastic intake on my 3,8, now I’m getting a small puddle of coolant on the aluminum intake in one spot. Any suggestions? The motor was siezed, the shop said to junk it….boy were they wrong! Car runs like a champ!
Thanks
i have a 2002 gp 3.1 engine with this problem and dealer said it was the intake gaskets….does this engine have the same plastic intake plenum? after reading all the crap about these i wanted to replace but cant seem to find one of these for a 3.1 engine. any advice???
I am currently working on my 1995 olds 88, 3.8 ltr. The upper manifold was leaking into the cylinders, also the lower intake gaskets were cracked in about 10 places. No water in the oil only into the cyls. Once you are doing the upper you might as well do the lower, its not that much more work. I also am changing out all bolts to rid my engine of the junk GM used. I am using Grade 8 Flange head type. I installed the lower today and they worked great. They are 5/16–18 thread–1 1/4 long. I bought them at our local hardware store. I am also changing the upper intake bolts, but they are mm, but I found a goo style and I beleive they will work. All other bolts will be Stainless. This not the cheapest way to go but I am sure it will be a better job than the dealer would do for a ton of money. Good Luck all.
Changed my manifold and now Engine won’t start. It ran but missed on cylinder 6 due to coolant leakage before manifold change. It has spark when cranked with plug pulled and held against a ground. Fuel squirts out of schrader valve when pushed and I can hear pump run when key is on. No codes and good cranking. All wires were reconnected properly. Help!!
Changed my manifold and now Engine won’t start. It ran but missed on cylinder 6 due to coolant leakage before manifold change. It has spark when cranked with plug pulled and held against a ground. Fuel squirts out of schrader valve when pushed and I can hear pump run when key is on. No codes and good cranking. All wires were reconnected properly. Help!! i am having same problem
Thanks, this really helped out alot, cost me 250.00 thats with the manifold, spark plugs, and wires , and the 25 $ tool rental for the Belt Tool, and also an o2 sensor on my car. and add 9.50 for lunch.
Only problem I’m having now is that my car is surging while in drive at a stop light. If i shift in to N i don’t feel it, So i’m not sure If i missed something, or something else is going wrong with the car now.
Just replaced the plenum and lower gaskets on a 97 Buick LeSabre. It had 174,000 on it before the plenum let go.This web site had great information and the directions were excellent. Bought the plenum from this site, which is a good value, and if you call them with any questions they are outstanding gietting getting back with you. cost for all this was around 230.00. This site saved a lot of money. Thanks all.
The above pictures dont show up. Can someone please give the tightening sequence for the upper intake bolts?
This page saved my bacon! It worked!
What happened to the pictures? I couldn’t have done it without them.
No offense to the DIYers out there, but I found a shop (a real shop, not a back yard) who did the job for $140 out the door. It was under $100 for the intake. If DIY works for you, do it. But know that the part cost varies greatly from one part store to the next, and so does the labor. If you prefer to have someone else do it, it CAN be done on the cheap. Especially if you do it before it is an issue like I did. During an oil change, the tech mentioned it and I took it to another place to have it done with no “just because” extras.
2003 Monte SS
Repaired at 90,000
14,000 on repair
Hello webmaster
I would like to share with you a link to your site
write me here preonrelt@mail.ru
This is great stuff — I could really use the pictures that are dead links. Can you email them?
Kent
Tank you for this grat info — I too,could really use the pictures that are dead links. Can you email them?
erhard.hartman@grc.nasa.gov
One month ago I had the intake manifold replaced on my 3.8L Regal. Since then I found it has not run well. About at week after that the car conitued to stall and the scan showed a failure in the throttle body sensor. We replaced it and th car ran well for about a week. I have noticed a slight vibration on acceleration. Today I could smell coolant, opened the lid and the top of the engine (below the new manifold) was covered in coolant. My mechanic just called and indicated that now the lower intake somethingorother needs to be replaced as well. They are honest and have promised to give me a discount as ‘it should have been done before’. My question is this: is there a chance that failure to do the lower casket may have resulted in damage to the rest of the engine. The car has 240K and up until this problem has never had any major issues. I am hoping to keep the car until it reached 300K, but now I am not sure.
Thank-you for some hope at last!!!
I cannot open the pictures. Could you please e-mail them to me?
I sure appreciate your posting this info!! Peace, Mark
Great information…
I cannot open the pictures. Can you please e-mail them to me?
Thanks alot,
Jack
can i install a series 2 intake manifold on a series 3 motor?
Can you please e-mail pics? Thanks!!!
i would like to have the instuctions to complete the lower intake gaskets on the 97 bonniville
Does the plastic tube that attaches to upper plenum gasket attach to hole on pressure sensor or just sit open on both ends for recirculating air??? Thanks, Tony, WI.
i just replaced the lower manifold on my 97 grand prix 3.8 non supercharged and now it is knocking never did this before until i changed out the lower manifold.it ran for 5 mins and then just died.any ideas as to what could be causing this any help is greatly appreciated.
Could you email me any pictures? Thanks!
THANKS, THANKS, THANKS… You’re the man Joe S. You save us time and money with your advice. YOU’RE THE MAN!!!
Thanks for the info. I’ll be getting started on my monte carlo pretty soon. I thought it was a head gasket. It was leaking a lot of coolant until i replaced the water pump. It didn’t seem to leak at all after that but then broke down 2 weeks later and was hydrolocked like you said at the top of the article.
Could you please email the pictures on how to repair GM 3.8L Intake manifold?
Thanks
Another important step not mentioned here is to replace or at least clean out the coolant inside the EGR tube which is located on the lower intake. If your lower was completely full of coolant like mine was, there will be fluid in the EGR tube. The instructions that came with my new upper intake say to replace it.
Very helpful article. My daughters 97 pontiac grand prix se has a leak in the upper intake manifold too. Mechanic wants $600 and said its almost all labor. Is there a standard time it should take to change the manifold like the dealers use? I would also like to see the pictures if you could email them. Thank you!
i don’t have step by step pictures but i did take a few while working on my 98 monte carlo so if you are interested in what yours may look like after removing the upper intake, leave a comment on this site or email me @ bearsd38@yahoo.com. if u replace the fuel injector o rings, which isn’t a bad idea, you will need a fuel injector nozzle puller. I’ve tried to get them over the lip of the nozzle, trust me, it does not work.
Is an oil change standard with this repair?
Where can I purchase the upgraded intake gasket kit for my ‘03 Impala 3.8?
Can you email me the pictures? I can’t open them…Thanks!
Hi my buick lesabre experienced this issue and i want to try and conduct the repair myself but i need the pictures please as they seem to be missing from the webpage, if you could mail them to me that would be awesome. Thanks so much.
I just did this on our 99 Gran Prix. It went OK, just took a long time, but this page had
some useful information.
One thing that I found is that you can’t turn over the engine w/o the spark plugs connected and installed - at least it didn’t
work for me.
Regarding the tightening sequence, I purchased a new replacement plenum, and the kit included detailed instructions regarding torque sequence, etc, plus a new, smaller diameter passage for the hot air coming from the EGR valve.
Also, the new plenum actually had the torquing sequence and torque value stamped in the plastic.
One other thing - make sure you change the engine oil after doing this…
followed your instruction and it went very well. I had water on top of the engine and removed it with paper towels.I removed the plugs and turn the motor over and there was osme water in the cylinders. After replacing the plugs tried to start the car. Now the car wont start. Anything I may have overllooked? thanks
I have a 99 pontiac grand prix gt with the 3.8L. I have had the intake gaskets and upper plenum replaced as well as spark plugs and spark plug wires and a coolant flush. All work has been done at a dealership. When i picked up the car i heard what sounded to me like a lifter tick and after about 10 seconds it went away. Now whenever i start the car in the morning or when engine is cold it ticks for 5 to 10 seconds. What could be the cause for this? I have had the car for 6 years and its never ticked or pinged or anything until i had this service done. Im going to go back to the dealer and see what happens. oh and gas pedal sticks when cold now to. i think accelerator cable needs to be lubed but it didnt do that either until after service has been performed,
Please e-mail the pictures for the upper intake manifold replacement to me, they will not open with the instructions.
Thanks for your time, Brian
I 2 am having a tapping sound. I’m hoping that goes away after I change the intake. Please Email the pic.s to me also.. vary cool web site. Thanks 4 all your help…
I have had 3 previous pontiac bonneville’s hydrolock (1995 - 1998 models) I purchased a 2001 SSEi thinking that the aluminum manifold with the supercharger would not warp and leak, but now I am losing coolant and have oily foam around the seal on my radiator cap, I called the dealer and they said the gasket still goes out on the SC model. Is the DYI repair proceedure the same as you outline above for the SC model and could you email me the pictures? Thanks so much
Hi
Excellent article and instructions..very helpful except that I too am unable to open the pics. Is there anyway you can alter your site so that i can open them or can you email them to me? Thanks again
Good article. Want to work on my 97 buick lesabre but could really use the pictures.Cannot open them .Could you e-mail them to me?
Thankyou.
followed your instruction and it went very well. I had water on top of the engine and removed it with paper towels.I removed the plugs and turn the motor over and there was osme water in the cylinders. After replacing the plugs tried to start the car. Now the car wont start. Anything I may have overllooked? thanks
97 pont GP SE with 3.8
lower intake manifold gasket leaken. Right bihind alternator, never locked but would get hella hot, no smoke no nothang some hesitation everynow and than still ran good. But when i took my upper intake plenum off i had oil sitten in the lower intake manifold. WTF everyone else had anit hmmmm well shes almost ready to go back together i better get back to it thanx. I used a chilton and just tore into the taredone
just wondering if i could have the url for the pictures for this article or maybe you have a pdf format to email me i would appreciate it thank a lot NICK
I own a 1997 Grand Prix GT with the infamous 3800.
Bought it for 500 bucks from the owner thinking the head gasket was blown, Bought the Dorman Intake, and the FEL-PRO Lower Gaskets, Will have it together tomorrow.
My situation was that coolant and oil were mixing, and it got up into the throttle body! never hydrolocked, but it was stalling out. I am thoroughly cleaning EVERYTHING as I go. Definetely CHANGE THE OIL!
I will post an update upon completion.
Please E-mail pictures. Thanks.
As far as running goes, it’s a success! However I will note when you have the LIM removed, look very closely by the pushrods, and just in general. As there can become chunks of clotted oil. That is like a blood clot in a human! (BAD NEWS!)
I was initially a little worried because it was doing the same thing. So I just let it run and idle for a while to get it to temp, gaskets sealed, had some moisture built up in exhaust. Nothing a little bit of driving out won’t fix!
Also after the oil change I performed, it’s not 100% clean, but I will change it again in a week or so. I still get a little of the “snotty” looking residual coolant that’s still ending up on the oil cap. The oil from the dipstick now is maintaining a healthy color/smell now.
And now I can personally endorse this as a fix for this great motor!
Also, DON’T FORGET THE EGR CHIMNEY SWAP!
Not trying to brag, but I did it without a Chilton/Haynes manual. I just got the torque sequences from forums online and utilized my sharp memory!
I had exactly the same problem today. Pulled the plugs and water/oil came pouring out. After all the plugs were out it turned over fine. I’m not interested in fixing it. The rest of the car is in nice condition. If you want it let me know, or I’ll sell it for scrap to my junk guy.
Kevin, Orlando FL, acreli34@yahoo.com
Please send the pictures, I can’t see them. I had the upper intake replaced years ago on my 98 pontiac Bonneville and now it looks like it’s leaking again. But the only place I actually see any water leaking is from a little metal tube coming out from the lower intake. If you look at the engine, standing in front of the car, its to the left side, right below the plastic upper intake. There is a small metal tube coming from the lower intake manifold, right under the plastic one. This pipe goes thru the belt pully tensionor and disappears. I can dry off the tube and see it start leaking. I’m wondering if this tube is my problem and not the plastic intake manifold again. Any Idea? I wish I knew the name of this tube but I tried to descrip it the best I could.
Thanks for any help and the pictures if you will send them. Robert
The instructions on this page were very useful and helpful. Thanks. However, after I completed the removal of the upper intake and then replaced it with a new NAPA brand upper intake manifold, gasket, EGR chimney, drained the cylinders, new spark plugs and refilled the collant. My 99 Grand Prix started very hard. Finally got it to start and it had a horrible miss and it steamed/smoked for 20 munites. Slowly it began to pick up the missing cylinders and smooth out.
How the car has a horrible hessitation/lag from idle to any acceleration. After the lag the RPMs pick right up as normal. Has anyone else experienced this problem? If so can you share with me what you found out the problem was. I have let the car idle about 45 minutes total.
Check ingine light is blinking too. I have yet to scan it.
Any ideas would be appreciated.
c_1475@yahoo.com
And yes I have already thought about trading it off. LOL
It is very help. IMy 1999 Buick Lesabra has problem this morning with white smoke and wait for 10 minutes, it can’t start any more. I search internet and find your message is very helpful. But the webpage miss pictures. I will replace the parts by myself. It is cold here Ottawa though (-20C). Hopefully I can get it done. Thanks.
I just replaced my intake and gasket. When I finished I noticed that when the engine is runnig and I try to remove the oil filler cap there is a large amount of suction holding the oil cap on. When I pull the cap off, the motor stalls. What is going on. I have never noticed this before. Is this going to hurt the engine.
I did this in March of 2009 on my brother’s 97 Le Sabre. It was not hard at all, and I didn’t need the pictures. The steps are written out well enough. Make sure all electrical connecters are FIRMLY seated while putting it back together. I pushed the one for the throttle body in but apparently it didn’t ‘click’ in. It wouldn’t start because it wasn’t opening and letting air in. Lucking my brother pushed on it and heard it click. After that it started right up. We changed the oil in it before starting it of course. He changed it again after 500 miles or so.
For about a day it ran rough with the engine light on. The next day it turned off and was running fine, so don’t freak out, it just needs to clear the coolant/water from the places you didn’t get to. Also the computer takes time to readjust itself.
You can do it, I promise!
J
To Craig:
I would guess the suction is due to the gasket not seating correctly. Also, make sure the replacement stem is seated correctly and all the way in, we had to tap it in with a piece of wooden broom handle and a mallet.
J
Я считаю, что Вы допускаете ошибку. Давайте обсудим это. Пишите мне в PM, поговорим.
Если нужна помощь сюда http://animalszone.net/bespozvon
2001 Buick Regal GS (Supercharged)
Problems started w/ coolant leaking (intake). Coolant must have loaded up in one of the cylinders and when I took off from a stop and stood into the throttle a bit, I ended up chipping parts of the edge of the top of the piston off and grinding them into/onto the cylinder wall, causing a knocking.
Motor is out of car on engine stand. Heads/intake off. Hoping to be able to hone cylinder, put new piston in and be good to go. Anyone have any thoughts?
I would really appreciate getting my hands on those pics. If you still have them can you forward them to me. If anyone reading this has them I would appreciate them
mcolbro@hotmail.com
Replaced both UIM and LIM on 97 non sc G.P..
TPS P0121 showed up right away after starting. The car runs great and seemed to be more responsive.
Replaced TPS, cleared code and it come back. If I hold the gas pedal down slightly while starting the light will not come after its cleared. On the next start up if I dont hold the pedal down the light will reappear.
Jusdt a note to you guys who have posted here:
1. YES, you do need to change your oil and filter! Even if it hasn’t yet turned to brown sludge, it’s cheap insurance!
2. Likely the reason it won’t start afterward is because you cheated and did NOT replace the spark plugs. Burned A/F can glaze them and you may even see a weak yellow spark, but trust me on this - try new spark plugs. I’d do it anyway since if you are doing this properly, the plugs are already out and those back 3 are a real pain to change later. Go ahead and remove the strut bar temporariily if it helps, your wheels won’t fall off. Changing your plugs is also far cheaper than all the sensors you will replace that won’t do any good. Make sure there isn’t any more liquid squirting out of your spark plug holes before you put the new ones in. (If you are like most of us, this will take 2 people…one to turn the key and one to watch the engine…)
3. Save the headache and DO NOT use a plenum from a wrecking yard. You’ll likely be doing this again in the future if you do. In January, 2010, the plenum kit (includes the gaskets & o-rings) from NAPA (part # 600-1186) will cost you about 130 bucks. (I am a shop and that’s what it cost me) From O’Reillys it is about the same. My local Carquest could not find one.
4. Make sure you don’t have gas leaks at the injectors after you put it all back together. Use the NEW injector o-rings that come with the kit. (Make sure you use the right ones) A pinched o-ring can cause you major headaches. There is no such thing as a little gas fire…
Guys if you installed a new UIM please make sure you put in a new PCV valve as the kit I bought did not come with a PCV valve or it was removed. I had P 108 MAP & P121 throttle position sensor codes set plus higher than normal idle plus some surging.
This might be useful !
2001 firebird v6 3800. I had a bad coolant leak in the front of the motor.
While getting prepared to replace the intake manifold gasket , found the leak by accident. The tension pulley assembly has a coolant flow through going to the heater hoses. There was a small crack in the back side of the tension pulley coolant flow through, allowing coolant to run down the front of the motor. This was a very simple repair. Good Luck
I was getting ready to change a thermostat because I thought it was leaking until I found this article. Leak is not bad yet, but I am pretty picky about leaks in general. Good info in this article. I have had very good luck with my ‘99 grand prix, upper intake made it 190,000 miles before it went out. Thanks for the info
Getting ready to tear apart my 99 GP SE, due to leak in this area, lot of this info helpful, hope i dont have these starting, seizing up problems u all are talking about. I will leave comment on here Thursday or Friday when hubby gets this done, have to wait to get parts from Omaha NE.
I had a shop do this work because i didn’t know this site existed. my car now has a engine knock around 1200 rpm. Any ideas?
can anyone please e-mail these pictures to me if they have them? Thanks
dobrogwt@sbcglobal.net
Good News! I found the series of six videos on this site on a 3800 manifold gasket replacement. I watched all six videos and am very impressed. This is a fairly complicated repair, this video is well done and very clear. Go to “Shop Now” above and then “Instruction & Video” and then automechs.com.
Or just go directly to www.automechs.com and click on instructions & video then type in manifold.
Good Luck!
Great article
Can you please email me pictures to tomhernandez@bellsouth.net
thank you for your help
Tom
Can u please email me the pics, thanx
can u please email me the pics, dluse.1@gmail.com
Just had the intake gasket replaced today on a 96 Grand Prix due to the common coolant leak. However, after driving it for the rest of the night the car died and needed to be jumped. the lights dimmed and battery light came on as if alternator wasn’t working. My guess is the shop didn’t hook the alternator back up correctly and dont think the alternator is bad. It’s difficult to find and follow the wires but seems everything is connected. Any ideas why the car is running from the battery and not the alternator?
About 7 days ago had complete flooding from Plenum into engine on a 98 Park Avenue with no turbo. Had the intake manifold gaskets replaced, valve cover gaskets and new plenum. Oil has been changed 3 times making sure all coolant is out. Car starts great, no cololant loss in 7 days, runs great, temperature excellent. All is good except during warm-up we get white smoke. Again, there is no coolant loss, and no real smeel to the smoke, it just seems like vapor. After 3 to 4 minutes as the car warms up the white smoke goes away. Any thoughts on this would be appreciatted.
As for those who said that had a knocking after the replacing the above, I had the loud knocking also. The mech and I both believe it is lifter noise. We drained the oil, added a quart of Marvel Mystery Oil and the rest new oil. After starting the car, noise lasted for 21 seconds then went away and has not returned. I plan to do another oil change in 30 days and add another quart of Marvel. We both believe the sludge of old oil/whatever was makin the lifters stick and the Marvel unstuk it.
J
HELP! So I did the intake swap like everyone said, lower as well as upper, and now the car cranks good and has fuel and spark but does not start!! Its driving me nuts!! Please help me!
Is there a way you can email me these instructions? I don’t see the pictures.
Thanks
Is there a way you can email me these instructions? I don’t see the pictures.
Thanks
The picture links are broken! can you please check it out? I am doing this repair and I sware I saw the pictures it yesterday but can’t see them today..
Thanks, the best description on the web.
Dmitri
I got one for ya. I have a 2002 3.8L non-supercharged engine that I replaced the upper intake plenum and gasket. After torquing everything evenly and through three steps I seem to have a leak, but not for the coolant. it it creating a sucktion through the crankcase. I hear a squeeling noise when at idle, but at higher RPM’s everythring disappears. When pulling the oil fill neck off you can really feel the suction. When the oil neck is removed the engine chugs or lopes and the squeel also disappears, then comes back when it is reinstalled. Any I deas? I have heard of blow by but never a suction like this.
Just finished this on my ‘98 Bonneville; works great. The Dorman manifold was in stock at my local auto parts supplier and sells for $129. My car was not yet severe and did not hydrolock, but it had the characteristic flood of coolant on top of the lower manifold.
Things to note:
- Double, triple check that every electrical connector and vacuum line you unplug is reattached when you assemble. Those of you who say the car does not start–chances are you’ve missed an electrical connector or did not seat it fully. Those of you who say the car runs rough–check all vacuum lines including the master cylinder.
- The Dorman kit includes a replacement EGR riser; make sure you install this securely. Mine was a loose fit. I knurled it by hand and applied loctite compound. I seated it by placing a small piece of wood on top the riser and gently driving it downwards with a hammer.
I changed the spark plugs as directed on this site. The old plugs did not appear damaged although some were slightly fouled. I turned the motor over with the plugs removed–no visible liquid was ejected from the cylinders. I completed this procedure before I reinstalled the alternator, since the rear spark plugs are difficult to reach in my Bonneville.
My oil level was above the “Full” mark, indicating that some mixture had likely seeped into the crankcase. I changed my oil and filter–it’s rather silly not to once you’ve gone to the trouble to change a manifold.
Good luck to everyone else who needs this repair. It’s not difficult and can be completed in an afternoon, but make sure you take your time cleaning the gasket surfaces, torquing the bolts properly and checking all the electrical and vacuum connectors.
Jake, in your case I would double-check that the PCV valve was replaced and correctly installed during this procedure. The Dorman kit includes a replacement PCV valve. You will find it at the far end of the manifold opposite the throttle body.
The PCV valve is easy to access with the engine cover removed. The assembly includes a sensor with wire harness, the valve, a spring and a pair of O-rings. If any of these are missing, a vacuum leak may result.
INTAKE BACKFIRE! blew the manifold into 3 pieces jus pickd up the car for short $ 2001 grand prix gt. was troing to start and kaboom!! the explosion knocked off a fuel line which im thinking cause the small fire.So i have it all stripped down and ready to reinsatll new manifold,but what caused this backfire ,i think i should be fixing this first . im told a relay,mass airflow sensor.ignition something,timing,ummmmm help! by the way ive never seen an air filter as dirty as this one was.wow.maybe never changed?! part of cause? loumike17@yahoo.com
can anyone tell me which way the white or clear tube with a bend on one end is for, and which way it is supposed to be facing? When I took the old plenum off the white the bend in the tube was toward the passenger side of the car. The new plenum the bend in the tube was towards the driver side of the vehicle. Oh, It is a 1997 Buick park ave. by the way !!! thanks !
could you email me the pics. Thanks
Can you email me the pics. Thanks
Hello.
I am a 19 yr old pregnant woman.
I replaced the upper plenum in a 1995 Buick Park Avenue all without pictures or any directions. I found this site AFTER I did my replacement, but this site was very helpful in letting me know I did eveything correctly.
My husband is currently working on an 2003 Monte Carlo SS. It was leaking coolant. He replaced the upper plastic intake. Put it all back together. Car starts and idles good. Accerlation the car sounds awful. Engine makes weird noises. Any advice?? PLEASE HELP!
Pontiac Grand Prix 1998 was losing coolant, low coolant light stayed on but the car would have coolant. Ran hot one morning and had white smoke coming out from under the hood. Replaced water pump and low coolant sensor. Hasn’t ran hot, but still has white smoke coming out from under the hood on passanger side when setting still. Is this a sign of blown head gasket? Please help.
what is normal operating temperature for these engines?–my daughters olds 88 running at 205-210…..seems hot to me