I don't know much about types of coolants, but I have been looking at the ongoing Dexcool debate. I have a jug of pink Prestone longlife that I bought 11 years ago. (this would have been the first LL coolant from Prestone Jug says "compatible with the extended life coolants used by all new car makers including GM DEX-COOL" I am looking to change the original coolant in my 1999 Grand Am 2.4. Is this coolant still OK to use? GM says 5 years for the life of installed coolant, but this is still in the jug. Is this stuff the same as DEX-COOL?