1998 Pontiac 3400 V6 anti freeze in cylinder *PROBLEM*

The manifold issue will cause coolant in the crankcase, not in the cylinder. I don't know what they've seen, so I cannot tell you whether their diagnosis is correct, but so far I find it believable.

I would agree with "hyundaitech". From your description, the problem is either head gasket, or possibly some sort of crack in the cylinder. The intake gasket issue cannot allow coolant into the cylinders.

I think that I would want the engine torn down before the decision to put a new motor in is made. Having said that, often, once you get that far, you are pretty much over a barrel. It's hard to back out once you have spent

Ian

I'm no expert on Pontiac intake gasket issues, but the one failure I do have personal experience with certainly did allow coolant into the cylinders. The plastic upper intake developed cracks (the manifold itself, not the gasket) near the coolant passages which circulate through the throttle body. This allowed coolant to be sucked through the throttle body and into the intake/cylinders. Engine in question was a 3800 Series II. The leak was bad enough to prevent the engine from running.

Steve

Completely different engine. Kind of like comparing oranges and pears.

There is no resemblance between the 3400 and the 3800 engines.

Yes, this is a big problem with the 3800 GENII engines. It is quite a different engine from the 3100/3400 engines.

Ian