Should I not use dex-cool antifreeze when I get my radiator flushed in a 2002 pontiac grand am?

I took my wife's 5 year old Cad to the dealer and asked the same question essentially. They said it didn't matter that it was 5 years old. It has only 44k miles on it and they say leave in the factory fill until it has 100k. That really makes little sense to me since it is not like oil but they own it for another 56k miles now.

Pontiac is indeed a GM brand and as such has used Dexcool since 1996 or so. However, lots of people switch to a different OAT or HOAT coolant after the warranty period; your V6 will suffer intake manifold gasket failure sooner or later if Dexcool is used the whole time. The 4 cylinders and V8s do not run coolant through the intake manifold gaskets but the V6s do.

Dex-cool has been reformulated long since and should be fine. Actually, most of the coolant on the market now is essentially the same thing, anything that says "long life" or "low toxicity" uses a similar formula.

The problems with the v6 engines was the intake gasket would leak the dexcool into the engine. Flush it and replace it with dexcool.