Overheating (Both the car and myself)

mazda
protege

#1

My '94 Protege overheats especially while the engine sits at idle speed. Coolant level is OK. No oil/coolant cross- contamination and no smoking from tailpipe. Both fans operate. Belts not slipping. I did discover that if I increase the engine rpm while the car is not moving it lowers the gauge back to/near normal. My theory is that the water pump is failing to circulate enough coolant to maintain the proper temperature within specs. But, before I change it (which involves removal of the timing belt and my consuming several aspirin), I would appreciate any advice/opinions especially if you have dealt with this problem. Thanks!


#2

Your theory is probably correct. The two most likely causes are restrictions in the radiator due to age and internal deposits, and a water pump with eroded impelllars (a worn uot pump).

The radiator can be checked with a pyrometer that “sees” temperatures. You can “map” the radiator with one, looking for anomolies in teh heat dissipation.

The water pump can be flow tested.


#3

Thanks for your help!


#4

That answer is perfect. Just also run the heater and fan full out on the way to repair shop.