I have a 2002 Chevy Blazer 4 wheel drive with a 4.3 liter engine with air. It is running hot on the gauge at lower speeds with air on. On the freeway at higher speeds with the air on it seems to run half-way on the gauge. There are no visible leaks anywhere. The oil and antifreeze look OK, unmixed. Could this possibly be a bad thermostat staying in the closed position?

-garnb

 

*Moving to 2nd Gen Tech* - Gen Chat isn't really for tech problems.

Could be a bad thermostat. Could be a failing fan clutch. Or it could be an airflow problem through the radiator.