Question about 1990 Chevrolet C2500
If the water pump isn't leaking, It's doubtful that it's the culprit.
Most likely the thermostat is stuck open, or stuck closed.
Given the age of the truck, and the higher operating temperatures of a diesel (i have a Dodge with a Cummins - so I'm feeling your pain on the fuel prices too), I would do a complete cooling system flush, new thermostat, and check for the upper and lower radiator hoses for signs of "bulging" where they meet the engine and the radiator. If they haven't been changed in a while, this is the time to do it, before they burst when you're in the middle of no where.
Posted on Jun 22, 2008
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