Coolant getting into Oil 98 3.8L Monte

[Ryan00TJ]

The latest UOA on my mother's 98 3.8L V6 Z34 Monte Carlo showed signs of coolant contamination in the oil. Not bad enough to cause damage as of yet but needs attention in the future. My question is what part has failed in the 3.8L to cause this leakage? I am well familiar with the 3.4 @ 3.1 motors intake manifold gasket leaking. Is it the same on the 3.8L? I've always heard these motors are pretty bulletproof when it comes to reliability, maybe these people have it wrong? I am pretty mechanically inclined as I have tore my LS1 apart along with it's T56 6speed transmission so replacing a few gaskets is not too overwhelming of a job. I am just asking if I should be on the lookout for any unforseen problems or snags? Any photos or writeups would be greatly appreciated! Thanks Guys!

 

[Matt_S]

The 3.8L has the same potential issue. On my '00 Monte, there was a recall that included revised fasteners for the intake manifold. You might want to check if such an update is available along with the new gasket. In addition to the recall, I (and a lot of other 3800 owners) have had the gasket replaced under warranty.

 

[Drew99GT]

Another problem is the nylon/plastic upper plenum will warp, and the EGR tube will melt it and allow coolent contamination that way.

 

[JohnBrowning]

9 out of 10 times it is the upper intake manifold leaking. Replace it with one from Dorman for $129.00. Napa uses the same brand as well. Make sure you check to make sure it is not under a TSB or recall. If their is a TSB or recall on it your dealer will do it for free in about 1 hour!

When I did mine I did the lower gaskets, injector o-rings, and the tensioner at the same time that doubled the time it took to do it.

Assumeing you have never overheated the vechile it is a very slime chance on the head gasket. If you take that silly engine cover off of the engine and look behind the throtle body where the upper intake manifold meets the lower you can usualy see coolant leaking their. It will normaly pool by the injectors as well. It is also common to get a misfire code and check engine light.