Peak Global Lifetime. Wally World or Even overpriced Walgreens had it when I was there. My mechanics were going to put back in DexCool, they said only use that. But I was like, I did some research, GP.net, and I am going with something else. They said ok, and put in the new stuff. My mechanics always tell me stuff like that I guess because they have the tendency to think WARRANTY in their head. So if you have done research on anything you change on the car, don't let mechanics push you into using what GM has specified if you know you can use something better.