failing heating passengers side 520i Touring

[gwuisman]

Hello,

Here in Holland it is freezing these days and my wife complained as passenger about freezing foots as the heating on her side only gives cold air wile the drivers side is nicely provided with hot air. The mechanic could not give a proper cause for the failure. Before he starts to rebuild my whole dash I would like some thoughts from this forum. I searched the FAQ but could not find any hint.

In my own search I noticed that the heating is working via a set of two cylinders (electrical valves ?) mounted on the back side of the fuse box. There, there is a vertical three pin connector. I don't know where the yellow cables are coming from. If I disconnect the connector, the passengerside gets hot air but the climat system doesnot work properly anymore. If connected I hear clicks and feel shocks through the cylinderset and hoses. Is that normal or does this point to an (electrical ?) failure in this set? Can these sets be replaced?

Has this set some infuence on the airco compressor? Sometimes I have to slow down because the compressor is getting on and off and causes irregulary working of the engine.

Thanks for your advice.

Gerard Wuisman.

[danzee]

I am supposing the Touring and Sedan have similar heating systems. There are two separate valves for the passenger side and driver side. They ar located on the firewall in the engine compartment in front of the driver. The auxiliary cooling pump is also in the same location. It is not difficult to replace the bad valve. Just make certain you clamp off the hoses leading to it before disconnecting them. That way you will minimize the chance for air getting into the system and causing subsequent bleeding problems. Getting the valve out is not easy, but can be done with patience. The whole job took about an hour in my case. There's a good post seomwhere with photos. I'll try to find it.

Hello,

Here in Holland it is freezing these days and my wife complained as passenger about freezing foots as the heating on her side only gives cold air wile the drivers side is nicely provided with hot air. The mechanic could not give a proper cause for the failure. Before he starts to rebuild my whole dash I would like some thoughts from this forum. I searched the FAQ but could not find any hint.

In my own search I noticed that the heating is working via a set of two cylinders (electrical valves ?) mounted on the back side of the fuse box. There, there is a vertical three pin connector. I don't know where the yellow cables are coming from. If I disconnect the connector, the passengerside gets hot air but the climat system doesnot work properly anymore. If connected I hear clicks and feel shocks through the cylinderset and hoses. Is that normal or does this point to an (electrical ?) failure in this set? Can these sets be replaced?

Has this set some infuence on the airco compressor? Sometimes I have to slow down because the compressor is getting on and off and causes irregulary working of the engine.

Thanks for your advice.

Gerard Wuisman.

[danzee]

For starters look at this thread. http://www.bimmer.info/forum/showthread.php?p=117844#poststop

[gwuisman]

Danzee,

Thanks a lot for the answer and the link. The pictures are showing the valve set I focused on. Are these valves repearable or do I need to buy a new one?

Gerard Wuisman.

[danzee]

The valve can be separated from the assembly and replaced. However, some people have reported success in banging on the stuck valve and freeing it up. Others have taken them apart and made repairs. Certainly replacement is the most reliable.
My humble recommendation is to try tapping on the valve to free it up, and replacing it with a new part if that fails. Even if the tapping does work, I would expect it to only be a temporary solution.
Dan

[gwuisman]

Today I replaced the valve set. A job of 45 min. Now I have hot air on both sides again and became some kisses of my wife. But at the passengers side however the air is cooler than on the drivers side. I need to put the passengers side temp controle 3 degrees Celcius higher than that on the drivers side. Any views on how to solve this (last?) problem?

Thanks,

Gerard Wuisman
1993 520i Touring