also after losts of thinking these are dexcol motors (dexcol coolant) might have restricted coolant passages because dexcool does bad things to orings and other parts try back flushing and plain old flushing and use your favoritee brand of anti freeze to replace because after talking to a prestone rep a couple years ago any antifreeze made in the last 6 or so years has been formulated to modern standards with out nasty results of dexcol and some other factory coolants