heater blows hot until I stop then cool air blows in

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Jan 11, 2010 | 8:10 PM

jennkent5454

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heater blows hot until I stop then cool air blows in

1994 siverado 1500 5.7L

I just replaced the heater core today and when testing it the heater would blow nice and hot while driving, then when stopping at a red light the air would turn cool. what is causing this problem?

Jan 11, 2010 | 9:03 PM

MDTAHOE

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From: Bowie, MD

Is the coolant level full?

Jan 11, 2010 | 10:00 PM

jennkent5454

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Quote:

Originally Posted by MDTAHOE

Is the coolant level full?

yes I think so, I will check, will this have something to with it?

Jan 12, 2010 | 5:41 AM

racerx55

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if its low it will not move coolant through it at idle.
another possibility is a slighly kinked hose, that allows some flow when its revved up only.

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