1987 ford Third LAX v6 3.8. When
the weather temp is 65 or higher
the temp gauge gets up near high
but doesn't overheat. When temp
outside temp. Is 55 or lower the
temp gage is right in the middle.
Could this be a thermostat
It could be off a little, I would go ahead and change it out and flush the system with a good flush and you should be fine.
It could be a thermostat but your car should not run at the high end of the gauge at 65 degrees which makes me think you need to do some maintenance to the cooling system. I would replace the hoses and thermostat, flush the engine and radiator and install new coolant 50/50 with water. I would also put a bottle of Water Wetter in the radiator.
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