Individual temperature control intermittant

[borderchris]

Hello all! I have a 1989 535i with a good aux fan, ice cold r134 conversion and I believe a good heater core. However, yesterday, the left set of vents only started blowing hot air whilst the others blew nice cold air- I fiddled with the left temp control up and down for a while, but no luck. Anyway, after a few hours, she blew cold again. Is the dial itself bad, or is there a sticking valve in the heater core? Thanks!

Chris

[colo525i]

More likely a sticky heater valve. Have someone adjust the controls from hot to cold over and over and rap on the heater core with something (hammer pliers etc...) Mine would stick on until i did that, now no problems.

[525SEI BRIT]

More likely a sticky heater valve. Have someone adjust the controls from hot to cold over and over and rap on the heater core with something (hammer pliers etc...) Mine would stick on until i did that, now no problems.

I have have a very simmaler problem, witch bit should i be hitting exactly? sounds like an easy fix as ive already pulled the controls all apart to no avail!

[ThoreauHD]

That's the symptom of a heater valve being stuck in the default open position. I just replaced mine, cause I hate heat, but you can bang on it if you want. Sounds exciting.

[525SEI BRIT]

That's the symptom of a heater valve being stuck in the default open position. I just replaced mine, cause I hate heat, but you can bang on it if you want. Sounds exciting.

i don't mind banging on it for a bit, cant do anymore harm, coz its allready broken!! but not sure exactly which bit needs a good old banging exactly!!

[Paul in NZ]

right hand rear of engine compartement,ther are two valves probably hiding behind(under) a flat lastic panel...i think there is a link to some pics on e34 .net,
http://www.bmwe34.net/e34main/Maintenance/Electrical/HeaterValve.htm

[shogun]

see my write up how to check the heater valves
http://www.bimmerboard.com/forums/posts/380566/