I have a friend with an 02 duramax. A couple days ago it began overheating and the heater starts to blow cold. If you romp on it pretty hard the heater starts blowing warm and the truck will cool down some. Now is it headgaskets? I am just going by what he is telling me. We replaced both t-stats last night and it fixed it for the evenig. It idled in the driveway for 30-45 min and stayed at a perfect 192. He drove it home with no issues. Drove it to work with no issue. Drove it around this afternoon and it began to overheat again. Anyone???
