I need to have my coooling system flushed and antifreeze replaced. I've been told by the mechanic that does all my major work that the GM "pink" can cause corrosion problems and I should go with with the ethelene/glycol mixture. My son also informed me that there is a class action suit pending about the GM "pink" antifreeze. However, he could not be more specific than that. My question is should I stay with the GM or GM approved antifreeze or go with another type?