Intake Manifold gasket replacement

A friend of mine bought a 2002 Grand Prix a few months back and just found out via her check engine light and follow up inspection that her intake manifold gasket needs to be replaced. She asked me what is involved in such a repair, and what kind of cost she is looking at?

The attached link provides a basic idea of what’s involved,
but understand that it’s a lot more work than it sounds. Actually doing the job is time consuming.

I’d call around for quotes. Labor rates vary regionally, and the cost is almost all labor.

She just found out that the warrenty she got when she bought the used car will cover it, and thus no out of pocket cost for her. Since they are doing that work at no cost to her she has decided to go ahead and have a tune up and full radiator flush done at the same time.

How does this gasket go bad?

Cool. It’s good to hear good news for a change.

How does it go bad? Poor design. Differences in the coefficient of thermal expansion between the manifold material and the heads. This is one of those cases where the owner bears absolutely no responsibility for the failure. It would happen regardless of how well the vehicle was taken care of.

She is scheduled to have it repaired next monday, the place doing the work said she could continue to drive it till then with no damage to the car, is that correct?

Well, she’s definitely better not to if she can avoid it. A lot depends on how much coolant the engine is ingesting.

I would drive this car as little as possible. Although, if the intake gasket has been leaking for a while damage may have already been done.

My 2000 Blazer was losing about a pint of coolant a month due to a leaking intake manifold gasket at 44k miles. My trusted mechanic found a few drops of coolant in the oil at the next change. He insisted I take it to the dealer immediately to get the gasket replaced (the dealer split the cost 50/50). His reasoning was that any coolant could displace the oil from the main bearings causing major damage.

Ed B.

that is what I thought, I was shocked to hear from her the place she is taking it said it wouldn’t do any more damage to the engine.

He was right.

Your crankshaft rides on a pressurized film of oil between its wear surfaces and its corresponding sleeve bearing surfaces. So do your connectng rod bearings. The oil is pumped through channels and holes in these parts to force the oil in there, and its resistance to flow (viscosity) creates the pressurized barrier. These bearing surfaces sustain a lot of lateral force when the cylinders fire, and they do distort sideways, making this fluid barrier critical.

The pressure comes from the forcing of the oil through these small spaces by the pump. Thin fluids, like coolant, not only don’t hold the surfaces up as readily because they run off too easily, they also run through the spaces too readily and the pump cannot maintain the fluid pressure as well. Thus, the coolant cannot maintain suffucient pressure in the bearing surfaces to withstand the pounding. Bearing failure, seizure, can result.

Coolant does a fine job lubricating your water pump, but it does a poor job lubricating your crank and rod bearings. It’s way too thin to work well in that system.

Well I told her and her response was it’s covered under warrenty so if it goes she gets a new/rebuilt engine. So I said okay…

Ouch. Talk her out of that. She can easily damage the engine to such an extent that its life is significantly shortened, but doesn’t actually fail completely until after the warranty is up. I.e. and engine doesn’t only have 2 states: good condition vs. broken. If she think that somehow she’ll be able to deal with that retroactively she is dreaming.

The warranty provider should be giving her a loaner.

The first thing I would do is check the engine oil and make sure that it’s not diluted with engine coolant. If it’s not then it should be ok to drive.
If it’s contaminated then I’d drive it as a little as possible, if at all.

They may gladly jump in with warranty on an intake gasket. A trashed engine could possibly cause them to develop a change of attitude about the entire thing.

According to the place that will be donig the work she will be okay, I advised that it would be better to just let it sit, she believes them…so her risk.