My mother in law just bought a 2005 Buick. On the coolant bottle it says Dex-cool. First time for me. Inside it is red and gungy. With a red scum on the side of the bottle.I have read up on the forum on Dex-cool but I still can't decide to flush it and refill with Dex-cool or flush it and refill with Prestone all vehicle long life. i have read horror stories on Dex-cool and am leaning to ending the relationship before it starts. Plus Ace Hardware has the Prestone cheap after rebate. Thanks.