Heater blows cold air?

1994 CHEVROLET SILVERADO
209,000 MILES • 7.4L • V8 • 4WD • AUTOMATIC
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THORR389
  • MEMBER
  • 1 POST
I changed the blower motor and the thermostat the coolant levels are good. I've checked the blend doors are opening and shutting like they should but the heater only blows cold air. I changed the water pump around the middle of last summer and it has around 20,000 miles on it. When it is at normal running temperature, which I believe we I am 190, both heater core hoses are cold, they do not even get warm at all, and the truck does not overheat at all.
Dec 27, 2022 at 8:47 PM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,240 POSTS
Hi,

If both hoses are cold when the heater is on and the engine is at operating temperature, the heater core must be plugged. Did you try flushing and backflushing it?

Let me know.

Joe
Dec 28, 2022 at 1:19 PM
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