1989 Cadillac Deville heat comers and goes

Tiny
TIM GONSAOREK
  • MEMBER
  • 1989 CADILLAC DEVILLE
Heater problem
1989 Cadillac Deville Front Wheel Drive Automatic 90,000 miles

I had my radiator replaced along with the thermostat, flushed twiced and bled. My hear works as long as I lay on the gas petal rea;y hard but as soon as I back off or just sit and idle it just blows cold air. I have had 4 mechanics check it out and none can figure out the problem.
Why does my heat not stay on all the time and turn cold?
Wednesday, February 11th, 2009 AT 9:51 PM

1 Reply

Tiny
FACTORYJACK
  • MECHANIC
  • 4,159 POSTS
Highest probabilty is the heater core being plugged or restricted. The low flow allows the fan air to cool it, much like a radiator. The second is a low flowing water pump, but you would most likely have an overheat as well. You can try backflushing the core in reverse direction, or just replacing it.
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Wednesday, February 11th, 2009 AT 10:23 PM

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