Mechanics

NO HOT AIR WHEN HEATER IS ON

1998 BMW 740

Heater problem
1998 BMW 740 V8 Two Wheel Drive Automatic 145000 miles

When I turn on the heater or defroster no warm air comes out of the vents. It just blows cool air. When using the A/C or just the vent on cool everything works fine. I just can't get it to blow warm air.
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DBP
May 31, 2009.




It is very possible the heater valve has failed and will require replacement.

Dr. Hagerty
May 31, 2009.
Is this something that is located in the engine compartment or is it under the dash? Is there a way to test this valve before replacement?
Thanks.

Tiny
DBP
Jun 1, 2009.
It is under the hood. It is on the fire wall, just follow the heater hoses. Testing is done by turning the heat on and feeling the hoses to the heater core, if they're cold the heater valve is suspect and at that mileage they have a high failure rate, go to Realoem. Com for the price and availability of your heater valve.
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Dr. Hagerty
Jun 1, 2009.

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