Mechanics

CHEVY OVERHEATS WHEN THERMOSTAT IN

1988 Chevrolet Blazer

Engine Cooling problem
1988 Chevy Blazer V8 Four Wheel Drive Automatic 70000 miles

I have an 88 K5 Blazer with a 5.7 liter. I replaced all hoses, radiater, water pump, thermostat and housing. Also replaced the heater core. The truck never overheated before but was leaking every where. After I replaced all this it began overheating. When the thermostat is in it only gets hot on the P/S of the radiator. The lower hose, heater core supply and return line, and the thermostat housing all get hot along with the P/S tank on radiator. The upper hose and D/S of tank stay cool. Some one give me some thing before set the dang truck on fire.
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88K5
December 14, 2009.



Almost sounds like the wrong water pump. Which belt drive system do you have? If it's a serpentine with the pump driving off the back side the pump is reverse rotation. If it has V belt drive to the pump it is standard rotation. That can be a PIA from 87-89 because they used both drives depending on the options.

The other thing could be the thermostat is in upside down. OR it is a bad one OOB. Seen that happen more than once.

Tiny
SWilliams
Dec 18, 2009.