GM is not the only manf that uses DexCool. And second, DexCool is perectly fine as long as the system never runs low and it is changed out when needed. A friend of mine who is a GM World Class Technician, not many are this, has educated me on DexCool. Too much to list here. I have had it in 4 cars and never an issue.
My 99 had the original Dexcool 130,000 miles and I just changed it out. The radiator was completely clog free and fine, the hoses were not degraded, just 10 years old and my UIM gasket was not degraded away either. I changed the UIM and gasket since both were original though. Lots of BS out there and DexCool to this day.
I have to agree with you though, I too thought my 3800 would not have a well known issue like UIM gasket and manifold issues. Very disappointing but lucky I could do the job myself.
Isnt it the LIM gasket that goes? Typically have plastic ones from the factory which have a metal replacement available directly from GM.
I didnt pay much for it and I had all the repairs done at the dealership that way it can be on record and I am kinda strapped for time right now. I generally like to do my own work on my cars/bikes.
Question: did they leave the heads on or go all the way?