[ssgharkness020147]

Start by replacing the T-stats (there are two). Napa has the best prices at about 11.00 a piece. If that does nothing for you check the fan clutch and make sure it is good, if you went through any deep water off road while the clutch was enagaged you very well could have fried it, Lynch HUMMER will have the best price on a new one. The cooling stack could be all gummed up with crap, the only way to REALLY get it clean is to disassemble the stack and pressure wash everything individually. Other then the water pump could be going out, but I would do the t-stats and check the fan clutch before you start digging in to the mess of a water pump replacement.