I did the oil change, checked the coolant and noticed scum on inside
of coolant fill cap, stuck my finger inside and the finger was covered
The drained used oil was black and normal looking.
My friend found this somewhere. I can't believe the problems with
this car. The intake manifold gasket was changed at 30000miles, now
Head gasket failure 3.1 / 3.4 / 3.8 GM engines.
--Scum on inside of coolant cap, and oil in the coolant tank
-- at first the leak is during the combustion stroke, oil with
some combustion gases enter the coolant system. (this must be the
state you are at).
Later, as the head gasket continues to fail and the passage opens up
coolant will enter the piston, and cause steamy exhaust, excessive
gasses in the coolant can damage rad hoses and radiator.
-- can be checked at the dealer with a device the detects combustion
gases in the coolant.
-- if test is positive then both heads are removed, and tested and
shaved for flat, then reassembled with new head gaskets, and new
This is an expensive repair, running in the ??/ well over a thousand
dollars I'm sure. The car is probably scrap, even so it looks like
Its a do-able repair at home, but will take 3 days with a wait time
for the heads to come back from the shop. Probably a week at least.
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