AC Expansion Valve

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Radical Racing
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Joined: Mon Mar 11, 2013 12:06 am

AC Expansion Valve

Post by Radical Racing »

Having replaced everything else it seems I am down to replacing the AC expansion valve as recommended by a professoinal AC guy. Unfortunately his shop does not work on imports. Bought a new valve from Bav Auto but I cannot figure out where it goes and if it is correct. Is there a diagram somewhere or can someone please post a photo showing a correct part for a '89 635 Csi and its location?

Second problem: as we all know there are three sliding knobs located in the center of the dashboard that control the vents for the heating and cooling systems. The top one in my car does not have the full range of side to side motion that the two below it do. It moves to about 1.5 inches short at each end of its travel. Something is restricting it and I think it is the vent flap. I have separated and disassembled the cover plate surrounding the three small rectangular knobs and the round fan speed & hot/cold temp dials. Before I start taking mores things apart underneath the dash, I am hoping someone can post a photo or diagram of this vent and cable system. All I see now is a cable running from where it is attached to the top slide mechanism and disappearing toward the firewall into a maze of cables and wiring.

Thanks in advance for any assistance offered.
francoid

Re: AC Expansion Valve

Post by francoid »

Hi, where are you located?
Thanks
Radical Racing
Posts: 47
Joined: Mon Mar 11, 2013 12:06 am

Re: AC Expansion Valve

Post by Radical Racing »

I'm in Northeastern California. None of the local shops want to touch BMW's.
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dwcains
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Location: Lutz, FL

Re: AC Expansion Valve

Post by dwcains »

I believe there are two expansion valves on the later US-cars with the dual a/c. There is a thread on bimmerforums you should probably read through:

http://www.bimmerforums.com/forum/showt ... S-OF-2016)
Dean
Lutz, FL

'85 635 CSi Euro #9402254
'87 Spider Veloce
'92 Spider Veloce
'08 350Z

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Da_Hose
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Re: AC Expansion Valve

Post by Da_Hose »

If you have a rear AC unit, then there are two expansion valves. If you only have front AC, then there is only one.

The front AC expansion valve is attached to the condenser. You have to open up the dash to get at that. I think it might be accessible if you remove the glovebox and lower panel on the passenger side. Getting at the condenser itself (to clean) or the motors requires you to dismantle the center console.

The rear expansion valve does require disassembly of the whole rear console, but unlike the front it is rebuildable. You can take it all apart and clean it out fairly easily. The front one is the real bugger as it has the thermocouple that goes through the firewall.

The 89 has a combination of cables (can't remember exactly what they are called) and switches. To get it apart, you have to pull the panel out a little and disconnect the cables first.

Jose
1987 M6 - My dream car
Radical Racing
Posts: 47
Joined: Mon Mar 11, 2013 12:06 am

Re: AC Expansion Valve

Post by Radical Racing »

Da Hose: I have lowered the glove box and disassembled the center console panels above the radio and disconnected the wire plugs that attach to the hot/cold and fan speed dials. Still can't see the Expansion valve nor where the vent is stuck preventing the upper slide from going fully left and right.

Very frustrating.
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dwcains
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Re: AC Expansion Valve

Post by dwcains »

The front expansion valve is inside the evaporator box, so except for the hose fittings, it's not directly visible. The shift console needs to e removed, and then the evaporator box.
Dean
Lutz, FL

'85 635 CSi Euro #9402254
'87 Spider Veloce
'92 Spider Veloce
'08 350Z

Image
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dwcains
Posts: 1465
Joined: Sun Sep 14, 2014 6:01 am
Location: Lutz, FL

Re: AC Expansion Valve

Post by dwcains »

Couldn't post this before because my hosting site was down:

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Dean
Lutz, FL

'85 635 CSi Euro #9402254
'87 Spider Veloce
'92 Spider Veloce
'08 350Z

Image
User avatar
Da_Hose
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Re: AC Expansion Valve

Post by Da_Hose »

Great pic, dwcains. Shows exactly where the expansion valve sits. I think it also illustrates that you have to remove the whole box and take it apart. Seems like if you HAVE to replace that front expansion valve, it is the right time to rebuild the whole shebang.

Jose
1987 M6 - My dream car
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