Rear A.C.

Post in this forum for topics relating to the interior.

Moderators: GRNSHRK, ron, bfons

Post Reply
tmoretta
Posts: 193
Joined: Mon Feb 06, 2017 8:30 pm
Location: Connecticut, U.S.A.

Rear A.C.

Post by tmoretta »

I installed a new A.C. compressor in my '88 M6 - vacuumed system and filled with new refridgerant. The front vents blow cold, the rear vents blow warm air. What's up?
User avatar
635sharknose
Posts: 513
Joined: Fri Sep 13, 2019 4:58 pm
Location: The Netherlands
Contact:

Re: Rear A.C.

Post by 635sharknose »

Was the rear AC working before the compressor died?

My first guess would be a bad expansion valve in the rear AC unit, part no. 64501377051
Paul
Image
Instagram: @635sharknose
1987 635CSi Bronzitbeige
tmoretta
Posts: 193
Joined: Mon Feb 06, 2017 8:30 pm
Location: Connecticut, U.S.A.

Re: Rear A.C.

Post by tmoretta »

Yes, after adding sufficient 134 front and rear vents were blowing cold.
tmoretta
Posts: 193
Joined: Mon Feb 06, 2017 8:30 pm
Location: Connecticut, U.S.A.

Re: Rear A.C.

Post by tmoretta »

By the way, is the expansion valve under the hood or under rear seat?
TimU
Posts: 280
Joined: Tue Dec 14, 2021 2:16 am
Location: Sydney

Re: Rear A.C.

Post by TimU »

tmoretta wrote: Mon Jun 06, 2022 10:46 pm By the way, is the expansion valve under the hood or under rear seat?
Under the rear centre console housing the AC unit:
https://www.realoem.com/bmw/enUS/showpa ... 4501377051

Also check out the "Voltage Regulator" in the engine bay. Part # 64511380659.
This valve controls / allows AC Oil to flow to the rear evaporator. When it becomes inoperative, the front A/C blows cold but the rear does not.
Apparently it can be taken apart and cleaned, or simply replace it.
https://www.realoem.com/bmw/enUS/showpa ... 4511380659
04/1986 635csi Euro spec
Australian Delivered, RHD
tmoretta
Posts: 193
Joined: Mon Feb 06, 2017 8:30 pm
Location: Connecticut, U.S.A.

Re: Rear A.C.

Post by tmoretta »

Does dismounting the "voltage regulator" require vaccuming/recharging the system?
TimU
Posts: 280
Joined: Tue Dec 14, 2021 2:16 am
Location: Sydney

Re: Rear A.C.

Post by TimU »

tmoretta wrote: Tue Jun 07, 2022 12:36 pm Does dismounting the "voltage regulator" require vaccuming/recharging the system?
Yes. You will need to disconnect the vacuum hoses to completely remove and replace the VR.
Likewise for the rear TX valve.
04/1986 635csi Euro spec
Australian Delivered, RHD
tmoretta
Posts: 193
Joined: Mon Feb 06, 2017 8:30 pm
Location: Connecticut, U.S.A.

Re: Rear A.C.

Post by tmoretta »

Thanks for the info and quick reply.
Post Reply