1998 BMW 740 no hot air when heater is on

1998 BMW 740
145,000 MILES • V8 • 2WD • AUTOMATIC
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DBP
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  • 2 POSTS
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.
May 31, 2009 at 11:20 AM
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DOCHAGERTY
  • CERTIFIED EXPERT
  • 9,603 POSTS
It is very possible the heater valve has failed and will require replacement.
May 31, 2009 at 2:41 PM
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DBP
  • MEMBER
  • 2 POSTS
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,
Jun 1, 2009 at 8:10 AM
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DOCHAGERTY
  • CERTIFIED EXPERT
  • 9,603 POSTS
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.
Jun 1, 2009 at 8:32 AM