why is my 1999 chevy s10 blazer overheating
just put new thermostat...replaced hoses....flushed radiator and it is still
running hot....when i turn my ac off temp goes down a little. I am not loosing
At your truck's age you might need a new water pump. The fins on the impeller may be worn down to nothing (antifreeze also takes its toll). When the truck is running squeeze the radiator hoses and see if they feel like they are under pressure.
You stated that the temp drops when you turn off the A/C, I would check for a good air flow through the radiator and A/C heat exchanger, bugs, dirt can build up and restrict flow, if it is all clean then the radiator maybe restricted internally so the coolant is not flowing as well as it should, one of those little lazer temp guns could show you how well the radiator is cooling and show any hot spots that it might have, indicating that the radiator needs replacement.
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