I will assume this is a V6 and not the 4 cyl. Ecotech engine. Sounds like
your intake manifold gasket is due for replacing. Shop around before you
get the work done, there is an old retired Chevrolet mechanic who replaced
mine for $100 cash, it only took him about 5-6 hours to do. The biggest
thing you can do to stop this from happening again is to flush all of that
old Dexcool out of the cooling system and replace it with your choice of
antifreeze. The problem with these gaskets going out again and again is
because the older the Dexcool antifreeze gets, the more acidic it becomes,
eating away those old or new gaskets. Personally I would not put Dexcool
back into the system, just for peace of mind.
As for any type of sealant in a bottle, I have no personal opinion, but I
will say this. If your coolant is old enough to be acidic enough to start
eating gaskets away, there is nothing you can pour into the cooling system
that is going to turn it back into a coolant. The problem is with the
coolant in the system and not the gaskets. If it is not flushed out and
replaced, it is going to continue to eat away gaskets until it finally ruins
your engine. Which is a shame, because these 3.1L engines are nearly
bulletproof.
Good luck,
Sharky
>> Stay informed about: Coolant question.