I have a 95 Park Avenue with the N/A 3800. A few months ago, I parked it cause it wouldn't turn over because 2 out of 3 of the front bank of cylinders were full of antifreeze. Now, me and my father dismissed it as headgasket failure, and I've been driving our 3rd car anyways, so it wasn't a huge deal. But I'm starting to miss the lounge chair on wheels, and I've looked into a few things, and it seems theres an upper intake gasket on the 3800'* that fails? would this cause the antifreeze to get into the cylinders? Prior to this happening, I had given the car to my mother so she could have something to drive, and I was driving me and my father'* third car, and she said she was putting more antifreeze into it, and there was some oil consumption (if I remember correctly) Basically, could this be the upper intake gasket that could be causing this? I spoke to someone offhand about it, and he said it could be that, and that with a new gasket and an oil change, it may be all set to go. Input?

http://www.bonnevilleclub.com/forum/...ic.php?t=33565

Classic signs and symptoms of the upper intake manifold failure.

An easy fix with several items discussed on this forum.

Are you referring to the link posted above when you say that, or is there another way? I'm just curious as to different ways to go about this.

EDIT: That link describes how to fix the EGR and the gasket, but what exactly happens? What, if any, is GM'* official fix for this? And aside from the gasket and a fix like this, what else is required?

The corrosive and hot exhaust gases eat through the plastic of the UIM, and then coolant leaks into the engine from the failed intake.

It may hydrolock the cylinders. If this happens at speed, that will bend a connecting rod right quick.

It may be a failure of the plastic upper intake manifold (described in the above referenced thread) or it may well be a failure of the gasket between the cylinder heads and the aluminum intake manifold. Both are well known to fail. Normally, you should not fix one without fixing the other.

To answer your question, GM'* "fix" is to sell you a new plastic upper and sometimes a new lower intake manifold, replacing all the gaskets and giving you another 40-60,000 miles of trouble-free service for $800-$1700.

There have been recent advances in gasket technology that we hope will fix the lower gasket failure problem. (see this thread: http://www.bonnevilleclub.com/forum/...ic.php?t=33945). This thread also discusses replacing the Series II plastic upper with a Series III aluminum upper and using an adapter for the throttle body.

If you do the work yourself, using the low-cost EGR fix, you can "git-r-done" for about $100. That'* figuring $40 for the lower gasket, $40 for the upper gasket, and $20 for JB weld, a pipe, and a sleeve. If you replace the upper, add $110. (The upper comes with gaskets for $150.) If you have the upper sleeved, add $40. If you have the work done at a (non-dealer) shop, maybe about $4-500.

Because this is such a common problem, you have a wide range of options.

IMPORTANT: Coolant is harmful to the bearings in your engine. To minimize damage, drain the oil and the coolant. Change the oil filter, put in some new oil, unplug the ICM so the car won't start without coolant, and turn the car over until oil pressure develops to try to flush any coolant from your engine bearings.

EDIT: Hopefully, you did not suffer any additional damage from the hydrolock when you tried to start it. Sometimes, the starter can be damaged or a connecting rod can be bent if one or two other cylinders fire first, pushing the piston with some coolant up into an uncompressible position. If that happens, the fix ain't so cheap.

If it'* diagnosed as a failed UIM, I hope to god that contaminated oil hasn't sat in your pan for long. It'll rust out the whole bottom of the engine. Drain it right away.

If it'* a failed upper (and it sure sounds like it) I have a sleeved one sitting on my workbench. $30 plus shipping.

I only send these to people who do their own mechanical work, with the proviso that it'* an ongoing experiment.

Check the previous threads for information.

Wow, thanks guys.

Bill: When you say 800-1700 for GM'* "fix", is that at a dealer or shop? I'll be doing this myself, would it be the $150 for the upper plus gasket, and then $40 for the lower gasket, if that indeed went as well? When it hydrolocked, i couldn't even crank it over with the starter, so at the worst, maybe the starter is gone. If I went the GM way, the car already has ~170k+ on it, so 40k-60k miles would be peach.

bob: you have a sleeved upper intake manifold? Could you show me what a sleeved upper looks like? thanks.