Classic/Antique Car Repair: 1965 Mustang, thermostat, running hot 289

Question
Is there anyway to test the temperature sending unit?  Should there be a difference in the resistance when it goes from cold to hot?

Answer
Hey Terry,

If your car it trying to run hot, I would replace the thermostat located in the top front of the intake manifold. The old 289 motors do not have sending units persay. Your temp gauge should be in the middle to upper middle after the car has warmed up.