Totally stumped!!!!

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Dec 11, 2005 | 12:01 PM

akramer1977

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Totally stumped!!!!

No heat in my 92 f-150 5.8 auto 4x4. Have replaced the; radiator,thermostat,water pump,heater core,and all hoses!!!!! Both heater hoses are very hot but, air in cab is lukewarm,,,,, last week it was scalding hot in there what gives? When I change the selectors in the cab they all apear to work even the temp control. It just goes from lukewarm to BRRRRRRR!!!!!!!

Dec 11, 2005 | 05:42 PM

bob arrington

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From: alaska

check underneath the dash, on the passenger side ,for a small vacum hose that is unplugged ,bob

Dec 11, 2005 | 08:15 PM

beer boy

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From: nova scotia, canada

why did u replace all that stuff. anyway i once put a heater core in and didn't take the plugs out. (my bad...lol) if u can feel that the hoses are both hot and there is no heat on the core (hard to get at?) then look for a restriction.
ps thats if the vac hose is ok.

Dec 12, 2005 | 03:12 AM

CowboyBilly9Mile

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From: Eastern WA

I'd suspect that the diverter door in the heater box is not diverting 100% of the incomming airflow across the heater core. Both of your heater hoses being hot indicates that you have adequate coolant flow thorugh the heater core.

Dec 12, 2005 | 07:02 AM

akramer1977

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where is the diverter door located in the heater box ? Easy ways to diagnose?

Dec 12, 2005 | 02:56 PM

73Custom

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From: SD

I agree with Bill, sounds like a door is stuck. I often find pens (fell down defrost vents) holding the doors open. Remove glove box and the cover to the heater core. Just to the left of the core is the door, move the hot/cold lever and you should see it move. Check that it closes all the way.

Marty