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No Heat

Tiny
ROBERTHARNEY
  • MEMBER
  • 1998 BMW 540I
  • V8
  • 2WD
  • AUTOMATIC
  • 118,000 MILES
1998 BMW 540i and the heater blows out cold air and the car is starting to overheat with around 118,000 miles. The heater will work from time to time but for no apparent reason. Typically it is now just blowing out cold air even when I set the internal temp to 90
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Tuesday, January 11th, 2011 AT 4:16 PM

7 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Start by replacing the thermostat and see what happens-
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Tuesday, January 11th, 2011 AT 4:30 PM
Tiny
DOCHAGERTY
  • MECHANIC
  • 9,601 POSTS
This seems like two separate issues to me. The overheating and the heater not working. The heater not working could be most likely caused by a cranky heater control valve, the overheating might take some searching to get to the root cause. When does it overheat, in traffic on a warm day? Or does it seem to just be running warm all the time? Rasmataz is correct for having the thermostat be the culprit, but lets see if it can stand alone so we can get to the root cause before we just start throwing parts at it. I am running around a bit today and will try to check in in a couple of hours.
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Tuesday, January 11th, 2011 AT 4:42 PM
Tiny
ROBERTHARNEY
  • MEMBER
  • 2 POSTS
Thanks guys. I just noticed the thermostat starting to change today. It would start rising if I were idle. I am in Chicago and it is 20 degrees outside. Once the car started moving then the temp would go back to normal. Now I have not yet replaced the water pump which is to be changed at 100K and I am at 118K. It is crazy the heater does not work. However, the heater will work from time to time.
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Tuesday, January 11th, 2011 AT 6:12 PM
Tiny
BMWTECHWAQAS
  • MECHANIC
  • 19 POSTS
Hagerty is right most likely you have a bad heater control valve, heater control valve is a key component. As far as overheating goes def check to see if thermostat is opening up. Ill be intersted to know what did you find out.
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Tuesday, January 11th, 2011 AT 6:18 PM
Tiny
DOCHAGERTY
  • MECHANIC
  • 9,601 POSTS
Me too!
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Tuesday, January 11th, 2011 AT 10:42 PM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Hey Doc you got ( SideKick ) time for me to demarry you buddy-this year is going good huh! Adios amigo esta lawago-
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Tuesday, January 11th, 2011 AT 11:03 PM
Tiny
DOCHAGERTY
  • MECHANIC
  • 9,601 POSTS
Nothin but LOVE right back at ya
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Wednesday, January 12th, 2011 AT 1:06 AM

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