Grand Prix

Intake Manifold Gasket May Leak Coolant or Engine Oil on Pontiac Grand Prix

Problem Description and Possible Solution

The intake manifold gasket may develop and external engine oil or coolant leak. In some cases, an internal coolant leak may occur causing coolant to mix with the engine oil. Our technicians tell us that operating the engine  with a coolant/oil mix can result in internal engine damage. Replacing the intake manifold gasket should correct these leaks.

Problem Data
RepairPal Verified
Average mileage: 130,737 (10,000–310,000)
Engines affected: 3.1L V6, 3.4L V6, 3.8L V6
16 model years affected: 1991, 1994, 1995, 1996, more1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
130 people reported this problem
Viewing 1 - 20 of 47 comments
This has been an awesome car with regular maintenance and normal wear/tear replacement parts but after replacing the AC condenser, it will run hot (210 degrees) and the TEMP light will come on. Fans both run, radiator is full. Runs fine in the cooler months and in the hot months (100+ this year)without the AC on. Noticed some oil residue around the opening of the radiator but no water in the oil, no white exhaust. Otherwise still squalls the tires and hugs the corners great. Any suggestions?
Oil found mixed into coolant resivour
Well, when i started my car i saw nothing but white smoke billowing from the tail pipe. Now car the rides extremely rough, i had it towed to a shop and they told me that i needed another engine, but after reading about how common this problem is i think i need a second opinion.
My car has had a head gasket change, plenum cover 2, intake 2 and exhaust gaskets changed. Yet I am still pouring white smoke and smelling like coolant. I am getting really frustrated. What is wrong with these cars!!!!!!
The coolant is leaking in to the engine,the intake manifold gasket is being replaced to correct.
Leak from intake under the thermostat housing
very common problem with these vehicles. GM had a class action suit against them and i was not informed of the suit until it was too late. i should have been reimbursed for the cost of replacing the manifold gaskets but was never notified.
my son checked the oil and it was very low.we checked for leaks everywere.but none to be found.and it dont smoke. noticed milky color in oil cap and radiator cap.most likley head gasket.also has a small skip but thats most likly the water in the oil.also head lights want work on dim.But over all great car that will fly. r ROLL TIDE
The one plactic elbow going into the manifold from the water pump is leaking

Had this problem from the get go.
Took it into the dealer for a ticking noise under the hood... they sent me out of the shop making me look like a damn fool that the noise is normal & anything worse is in my head (cuz I'm a girl?)
Smoke coming out of tailpipe... no matter where I took it they made it sound like a big job to do & they can do it when they are less busy which they rarely are.
So my dad (a smart guy but an asshole) said it is a simple & quick repair that he'll do when I change the oil next time... well that is not going to happen, I rather pay someone to fix it than to have him do it. Now I will go to the shop & tell them what to change & will update this post accordingly
Ruined my cat, had both img's replaced. Common issue with this car.
car miss-fires up until you get it above 2000 rpm but doesnt miss fire if its been on for awhile replaced the head gaskets intake gaskets all of them it fixxed the problem right up
im sure I have a blown head gasket a lot of white smoke from exhaust and car overheats get reduced engine power a lot have not fixed it
Leaking coolant from front of engine. Appears to be intake manifold. Not fixed yet. Leak is external only.
Coolant mixing with oil car running hot
Upper Plenum Gasket leak $78.99 Labor 2.5 = $162.50
Lower Intake Gasket leak $ 99.19 Labor 4.6 = $ 299.00
Plus Oil & Filter and Antifreeze

oil, filter, & antifreeze
sales Tax
Water in oil
engine light on. Engine overheated on highway. Had to replace upper and lower intake manifold gasket becuase it was leaking. Was quoted just to change the lower for $900. Went ahead and did upper as well and got another quote getting both done at same time for $575. Get multiple bids!!
My problem is the heater was clogged with dexcool so I flushed it and switched to the green antifreeze and the heat started working again. Then the thermostat had to be replaced. Now I'm going through coolant like crazy. Help
Upper and lower intake leaks. Throttle body is dirty .