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Frank · Joined: 10 Feb 2002 Posts: 67 Location: Howell, NJ USA

I do not have a repair manual for my '88 735iL. Could someone tell me where the HOT WATER VALVE is located. This valve controls the A/C inside the car. It directs the A/C to the vents. My problem is that 1/2 of my car (driver's side) blows warm to hot air. The other side blows the A/C air. I was told by the dealer that the HOT WATER VALVE needs replacement.

zs6xu · Joined: 17 May 2007 Posts: 3 Location: South Africa

Hi, just joined

found the same on my 91 730i, demister always blows hot - traced to valves in (my passenger RHD) side, one valve is stuck, going to dismantle tomorrow and feed back, looks like a common problem. took the plug out and put 12 v onto the pins, centre +12v and gnd on the other 2 - one valve clicks the other is stuck

Steven Baynes, 1991 730i 145 000km
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Amateur Radio, when all else fails

zs6xu · Joined: 17 May 2007 Posts: 3 Location: South Africa

ok, took the valve out with a bit of cussing and small cuts, opened it up and the diaphragms were shot and one of the solenoid pins was jammed, used some silicon spary and removed it and cleaned both with steel wool. The rest of the valve is ok but as a temporary job, just oiled everything and put it back together and back in the car, aircon now gets REAL cold and the valves work but for how long I don't know, will have to order a new one next week

Looks like there is no easy fix to this, I doubt they will sell little parts loose for the valves (diaphragms)

Cheers

Steve
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Amateur Radio, when all else fails

edjack · Joined: 04 Feb 2002 Posts: 3887 Location: San Jose, CA

I remember reading that there are (were?) kits to rebuild these valves. Check with your local dealer.
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Ed BMW CCA member since 1987 (Nr. 62319).
'97 540i 6 speed Aspensilber over Aubergine interior.