1998 BMW 740 no hot air when heater is on

1998 BMW 740
145,000 MILES • V8 • 2WD • AUTOMATIC
Avatar
DBP
  • MEMBER
  • 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
Advertisement
Avatar
DOCHAGERTY
  • ✓ASE Certified Mechanic
  • 9,606 POSTS
  • ASE Certified Mechanic
It is very possible the heater valve has failed and will require replacement.
May 31, 2009 at 2:41 PM
Avatar
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
Avatar
DOCHAGERTY
  • ✓ASE Certified Mechanic
  • 9,606 POSTS
  • ASE Certified Mechanic
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
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.