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'98 Buick LeSabre suddenly lost all coolant

What are the symptoms of of a blown head gasket versus a bad plastic intake manifold? The car is expelling lots of steam out the exhaust. It only ran hot for a few blocks before it was shut down.

A pressure test on the cylinders will indicate if there is a head gasket failure.

I did a compression test and got good even readings in the 160s, except for one cylinder which gave me 210 and a lot of coolant. Coolant could happen if either the head gasket or the intake manifold were bad, right? There is also coolant on the air cleaner side of the throttle body.

The plastic intake manifold is the first thing on top of the engine, and is the most suspect cause of the problem.

I say take it off, and check it out. They make new ones every day.

Rockauto.com sales them for a good price. <$100.00

I know those plastic manifolds have been an issue (practically the ONLY issue) on the 3.8L V-6s for years. If yours has never been replaced, it’s probably due. There was nothing you could do to prevent this from happening.

It was indeed the plastic intake manifold. The new one from O’Reilly’s was in stock and $116 including the seals and a new design short pipe that replaced the one that supposedly causes this problem. The old design carried too much exhaust heat too close to the plastic. It wasn’t too bad a job, even for a half fast mechanic. I thought it still had a problem when I started it up, but it turned out to be antifreeze that had gotten into the exhaust and needed a chance to burn and/or blow out. A five mile drive cured that. All is well. Thanks for your help and encouragement.

There is always a great feeling of accomplishment in fixing something yourself. Thanks for letting us know the outcome.