| I would check you radiator filler neck, if it is a rusty mud color and sludgy you have the infamous gm dexcool problem. It causes all kinds of problems with the cooling system including intemittant heat. If this is the case I would backflush the heater core, flush the entire system and use traditional coolant. Do you ever hear gurgling sounds on the right side of the dash when you raise engine rpm? If you do the coolant is low and or the heater core is plugged.
Dexcool is junk imho. |