74Vetteski

Was wondering why my engine is over heating all of a sudden (goes to red zone on heat gauge). The fan belts are good and the fan seems to be working. Fluid is level is OK. How can i tell if the water pump is working properly? What else could be causing this. If I turn the interior heater on the temp gauge goes down to normal operating temp. Could it be the thermostat?
Help welcome.
Peter

MasterDave

Very possibly it is the thermostat. They have a nasty habit of sticking either open, closed or somewhere in between. It's an easy change out so that's what I'd do that first. And get a good one! A hi-flow with the bleed hole in it is best. To check yours you can boil it in water and using a candy thermometer you can tell at what temp it opens (if at all), and it should open fully.

jamiejamison

The ZZ4 ran hot in my 80 vette untill I installed a Mr Cool alum rad with twin electric fan. Runs 160 now in the summer time.