[formulaross]

To TweakedGM: This is what I have done - gone back to the green ethylene glycol coolant and added a bottle of Barsleaks. If you have rust showing up, you've corroding something internally. Hey, I'm an engineer and I work for GM, but I won't use their new propylene glycol coolant in my past-warranty cars. Our Pontiac Vibe is under warranty, but guess what it came with from the factory? The good old green stuff, but then again, it's really a Toyota and not a Pontiac. Do the google search for the GM lawsuit info. GM has too much to lose by admitting a mistake. Their position is if everything is perfect, the new stuff is OK, which it is, but who lives in a perfect world?