1998 Olds 3.8 Liter Cracked Intake Manifold

[Guest]

A friend of mine bought a second hand 1998 Olds 88 with a 3.8 liter engine. He recently replaced the intake manifold (or as they called it, the upper plenum) as it had cracked. Is this a common problem for this vehicle/engine? Fortunately it was covered under a warrantee.

Any information would be appreciated.

[86 2dr.ltd]

Thats right !!!!! Thats the L36 and some genius or penny pincher at GM decided to make intake manifolds out of plastic, you know the stuff that shrinks,cracks, becomes brittle, and melts with little heat. Every forum from Grand Prix to LeSabre, 88's and even the W body forum have had topics on this. Heres one of them at the Bonneville club, the 88's brother car. http://www.bonnevilleclub.com/forum/viewtopic.php?t=2472

Hes lucky his went under warrenty many used car buyers are getting stuck with this repair and some are frying their enginesbefore they figure out theres a problem. No leakage under car is noticed just anti freeze loss.Every one will fail sooner or later. Way to go GM like you dont have enough reputation problems already.

[Sgt Art]

A tip. My son's 87 Trans Am was losing coolant at too high a rate. I did the standard checks for leaks by couldn't find anything. I checked and checked. Then I noticed a slight dribble where the radiator core attached to side tank (Plastic). Everytime you revved the engine a bit, the pressure would push the tank just a little bit away from the core and a trickle of coolant would appear and run down the side of the tank. Do this a couple days and you've lost a quart or two. It was very subtle and I almost missed it. Pulled the radiator and took it to a shop they fixed it and it's been ok. Okay, this can happen with brass and copper too, I guess, but that plastic has always bothered me.

I too am surprised that the guy got warranty to cover a 1998 model car. I think the base warranty on those cars is 36/36. Perhaps GM has a campaign on this problem. If you ask the service manager for assistance or maybe go to the zone manager for help they will fix the problem. They were willing to split repainting on of my cars that was 6 years old when the clear coat started peeling off. Another fine piece of work.

[Guest]

On these uper (3800 II) plastic intakes where do they crack? Most GM manafolds crack at the same place or places. Thanks for any info Ron.