98 Bonneville Intake Manifold or Head Gasket

"A.T" wrote

Before they do anything else, ask them to remove the plastic upper intake plenum and check for coolant inside the cavity of the lower intake manifold. I can almost guarantee that this is "the" intake manifold problem. You will need to replace the upper and lower intake manifolds for a long term fix.

Here is a picture of what they might find when they pull the upper plenum. Of course, the coolant should probably be orange instead of green.

Ian

or before removing the intake two simple things would help pin point the problem without taking a lot appart. A simple cylinder leak down test would eliminate the head gasket as the problem. Dont know how they come to that conclusion that its the head gasket without any real test. Not an issue I've heard of with 3800's. The next test would be to pressure test the cooling system. If the cooling system doesnt hold its most likely the intake.

"Bon·ne·ville" wrote

Believe it or not, it's actually quicker to remove the upper plenum then to do a cylinder leak down test. Plus, you can also just remove the throttle body and often see coolant inside the upper plenum from there.

Ian

Yeah on that engine it is, had my own intake off twice now... Took about a= =20 half hour for me. But for the guys at that shop it should of been=20 something they should of done to prove that it was the head gasket to the= =20 customer. What were they going to do if he paid for that job? Tear it down= =20 only to find good head gaskets and tack on the price of a new upper and=20 lower intake as well? I second that its an intake problem as well, no=20 disagreement there, just one the way they diagnosed it.=20

A.T. I dont know how good you are at working on cars or what tools you=20 have but if you want to take off the thottle body like Ian mentioned you=20 can check my pages out on this for a little help.=20

're still slightly under construction)If you find it to be flooded out on inside of your intake from a leaky egr==20 passage suck some of that coolant out with a wet vac and reattatch your=20 throttle body (about 85 inch pounds) and hook everything back up and get=20 it worked on.

btw I got a 98 also :)

The reason that the shop does not think it is the intake is because they say that antifreeze would not just be coming out two spark plug holes, but all. I guess that is probably true. If it is pooled in there, then when the engine turns over it should probably come out all holes. What do you think?

Well that might also depend on how well the gasket is sealing between the upper and the lower intake. If its pooling in there and the gasket isnt keeping the center ports sealed it might be pulling in more there. Also the "center" plugs might have fouled out from the coolant and may not have been burning it off there to give the appearance that its a head gasket. How many miles do you have on your car anyhow? If its got over 40k and its never had the intake repaired its definitely has an intake problem. I would have them start with fixing the intakes and before they go removing the heads make them do a cylinder leak down test as proof. They will most likely find that the heads do not need to be removed. If these people sound eager to pull your heads have the leak down test done somewhere else first. Just checking the center cylinder can quickly give them an idea.

Well, the problem has been solved. It was the upper intake manifold. After taking the engine apart to look at head gaskets they figured it out that it was intake. 680 dollar job, better than 1,000 though.

"A.T" wrote

If they only replace the upper intake, then no...the problem is not solved. Did they take the heads right off? I sure hope not, for your sake. It would be a waste of money. You should instruct them to replace the lower intake too, as it has been updated. Sounds like they have already finished the job.

Ian

This post didnt even show up for me...

The egr pipe comes in contact with the upper intake with the old lower. If they didnt replace it with the new lower it will only melt the upper again.

Yes, both upper and lower were replaced as well as spark plugs, oil and fluid. Thank GOD. Thanks. I think part of the problem was being a girl and they did not believe me...guess I showed them...ha ha. Thanks again.

"A.T" wrote

No problem...and yes....the gender thing can be a problem. Girls (ladies) are getting smarter and more car savvy as the years go on. It's a foolish shop that attempts to screw (in the business sense) female customers these days.

We have a female tech in our shop......she's pretty tough. She has a small sign on her tool box...."caution, I make boys cry".....heh heh.

Gotta love em....(women, which I do)

Ian

I got to get one of those signs. That is classic. Most of what I figured out about the car was online.

o.k., why could the engine light possibly be coming back on and the inside of the car smells like burning oil....also oil level seems like it is going crazy? Not my car, so just repeating what I was told. Could there be another problem that is because of the intake manifold going? The car has been running since Monday now with no problems until this morning. Any info, once again, would be appreciated. Guess we have to call the shop again.

I am wondering if you have contact GM yourself identify this problem to GM as a common problem like you already said. The way I see this problem as reported here is a design flaw. I truly believe that GM is responsible forthis problem along with other like Dex-cool claim that could result in engine damage if follow manufacturer maitenance schedule. It is true that they may not have done this intentionally and mistake can happen. However, if is a systematic problem that is well aware by dealer or user group like this one, it must be escalated up to GM if they want loyal support from consumer like all of us. For example, if you own a Toyota Sienna 1998, you will experience transmission problem regardless mileage due to design flaw that the one of the gear does not receive adequate lubrication. Toyota has contacted all their cusmoters with letter saying that they will replace the transmission free of charge when it fail. I have know two people (my co-worker) have this problem and both are very satisfy with the support Toyota has given to them. Toyota 4 Runner had cylinder head gasket failed due to design flaw few years before that. Once again Toyota offers the repair free of charge. They could afford this level of service because they believe in their product/design and most of all they want to earn customer royal support. I am a GM proud owner with three vehicles. Luckily I don't have any problem. The problem you identified perhaps not your fault and should be brought forward to GM. Go to gmcanada website ot gm dealer depend how you want to approach this problem. Voice your concern and seeking help / resolution from them. This new group has been very helpful to all of us to learn more about our car and become familiar to minor problem. But this problem is bit too much for us to deal it alone.

Just my thought!! Good luck with your repair! MN

"A.T" wrote in message news: snipped-for-privacy@posting.google.com...

"A.T" wrote

Engine light coming back on could be anything, it will have to be scanned to determine what that problem is. Inside of car smelling like burning oil....there may either be an oil leak, or possibly residue left on the manifold and heat shields from the repair. Any burning oil in the engine compartment usually will be pulled straight into the passenger compartment as the air intake for the passenger compartment is just behind the engine compartment. Sure...there is a hood seal...but it still leaks through.

Ian