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2000 Chevy Silverado C3500 w/ 454 engine?
Water Pump seems to be fine (just replaced it). The thermostat is opening and closing like it should. Temperature is fine at idle and at operating speeds.
There is no return coolant coming back out of the heater core.
What would cause this to happen?
There are NO leaks.
3 Answers
- RudedudeLv 41 decade agoFavorite Answer
Block or plugged heater core. Pull both hoses off the heater core and take a garden hose.Put the garden hose onto either heater core tube and turn on the water.It should flow easily through the core and out the other tube.If it does not you need a heater core.If it builds pressure then lets go I've just fixed your problem .If it flows easily and you still have no flow I'd have to see it to go farther Good luck hope I helped
GM tech for 20 years
