Heater

1986 BMW 535I
170,000 MILES • 6 CYL • 2WD • MANUAL
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VERLYN SWANSON
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  • 2 POSTS
I have a 1986 BMW 535i - the heater only blows hot air when the car is idling or slightly above. At higher rpm the air turns cooler. When you return to idle or lower rpm the air returns to hot. The firewall heater valve seems to be working fine, when you turn the temp control on dash from hot to cold it responds correctly. This is a recently purchased used car and I found that the interior temp. sensor had been totally disconnected and appears to be broken. It has a vacuum hose connection to it, which makes me think there maybe a connection to this sensor and my problem (since the temperature does seem to change with engine vacuum). I just don't know what the interior temp. sensor controls. Could this be related to my problem?
Jan 1, 2011 at 10:47 PM
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DOCHAGERTY
  • ✓ASE Certified Mechanic
  • 9,606 POSTS
  • ASE Certified Mechanic
The heater control valve is weak and needs to be replaced, here is the part number 64-11-8-390-132 The interior sensor is not the issue.
Jan 2, 2011 at 2:37 PM
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VERLYN SWANSON
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Thanks for the quick response. I've tried all the national auto chain stores in my area and the part is not available. Is this a dealer only item? Do you recommend any suppliers online?
Jan 2, 2011 at 8:46 PM
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DOCHAGERTY
  • ✓ASE Certified Mechanic
  • 9,606 POSTS
  • ASE Certified Mechanic
Realoem.com can sell it to you or you can call (619)444-2290 and talk to Autobahn dismantling. John would happy to ship it to you.
Jan 2, 2011 at 11:02 PM
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