Air-con BMW 635CSI M

[stevejordan100]

I'm sure this has been posted before but I can't find it. Since R12 gas was phased out air-con on these cars has been hit and miss. I am about to have a go at getting the air-con system working again.
What have others done, and has it been success full, or is their a new compressor you can buy that will deal with the new gasses that are now on the market.
Any advise would be good before I start on this project.
I also have another 635 CSI with the same problem

[Dan101smith]

BMW have a retrofit kit available to convert to R134a - it comprises a new receiver/drier, a new fill valve and a sticker.

I converted mine and it has been fine since (about 18 months).

[Brucey]

BMW have a retrofit kit available to convert to R134a - it comprises a new receiver/drier, a new fill valve and a sticker.

I converted mine and it has been fine since (about 18 months).

Presumably you have a late model E24? I think it is worth mentioning that early cars appear not to have compressors (or seals, right through the system) that are compatible with R134a.

If the kit is compatible, there will still be a dropoff in performance. To combat this, some folk fit a larger condenser. I'm not sure this is really worth it in a UK 'summer' though!

cheers

[Dan101smith]

No, I have an E28, but assume that the later E24 systems are the same. The standard system isn't officially R134a compatible. Except it is. You'll need to accept that it won't be quite as punchy as on R12, and it WILL leak a little gas over time, but it still works perfectly effectively.

Mine coped admirably with 35C ambient temps in Le Mans last June.

[Brucey]

which oil did you use and which model compressor (exactly) do you have?

I remember seeing a list of compressors (used on BMWs around this time) that were and were not compatible with R134a and most of those applicable to E24 were 'not compatible' but a few of the later ones 'were'.

cheers

[Dan101smith]

Whichever oil was used by the garage who re-gassed it, and I don't know without looking.

But you're over-thinking it.

The air con in the OP's car doesn't currently work. You can't (really) buy R12 gas any more.

So, put the new receiver/drier on, fill with R134a and run it. If it works - fantastic. If it doesn't, you've lost nothing.

[MSGGrunt]

Correct me if I am mistaken but, R-12 can be bought by the end user, just not bought for resale? I see all kinds of it for sale on EBay. If the conversion to R-134 is done you will need hoses that are designed for R-134 as they are lined to handle the smaller molecular size of the 134 refrigerant vs R-12. And don't even ask about the idea of using propane/butane mix as this will open up an entirely different can of worms, though some over on my Mercedes forum swear by it.

[dwcains]

No issue buying R12 on eBay, and I've bought quite a stash for my E24 and the 2 Alfa's. I'm in south Florida, so R134a, even with a parallel flow comdensor (from Classic Auto Air) I wanted the best cooling possible. The Sanden 508 compressor is a great inexpensive (~$150) upgrade, and bolts on with a set of $40 adapter brackets. New hoses cost me ~$80, so it's silly not to do those. The a/c system is one of those that really is an all or nothing job, if you want it to work optimally, and especially if the system has been inoperative for a long time. R152a is a new refrigerant that provides another option, and is slated to be the new default refrigerant, as R134a is phased out. It's already available in expensively, and if I have to open my E24 system again, that's probably what i'll recharge it with.

[Brucey]

But you're over-thinking it....

So, put the new receiver/drier on, fill with R134a and run it. If it works - fantastic. If it doesn't, you've lost nothing.

I disagree; if you just fill a system up with R134a, some oils used in R12 systems will react and turn to a load of sludgy crap that will scrap the entire system off.

cheers

[sharkfan]

My E24 M635 has been converted; I can't remember the details but AFAIK no components or even seals were changed. The things that were (IIRC) changed were the charging valves and the oil. The system has worked brilliantly for over 5 years without a recharge; my tip is to read the manual and set the sliders in their correct positions.

My 635 hasn't been converted but all the components appear to work (internal fan, cooling fan, temp control) and the system still has some pressure of something in it so I might look at getting it done.

[Dan101smith]

But you're over-thinking it....

So, put the new receiver/drier on, fill with R134a and run it. If it works - fantastic. If it doesn't, you've lost nothing.

I disagree; if you just fill a system up with R134a, some oils used in R12 systems will react and turn to a load of sludgy crap that will scrap the entire system off.

cheers

The old oil will be purged from the system during the first part of the re-charge cycle.

[Brucey]

The old oil will be purged from the system during the first part of the re-charge cycle.

it ought to be, but there is very often a residue left behind and that can cause problems.

cheers

[dwcains]

True - I used this stuff to wash out the evaporator and hard lines I reused:

http://www.amazon.com/Four-Seasons-6999 ... +fluch+kit

[slofut]

Steve, have you made any progress on this project?

I wonder if a parallel flow condenser with r12 would make a difference? I have enough r12 to refill once more. Charged it last summer and it would cool enough to make you wish you had a real AC. 95+ temps though, glad I have a GM truck... If it doesn't work though, I'd be out a condenser to re-work the system as a PF can't be cleaned, but at least I'd have the hoses in place. Tempted to go with propane/butane?

[dwcains]

R12 and a PF condensor will definitely make a large difference. It's all about heat exchange. I'd stick with R12, and have accumulated a nice stash from eBay. The listings may say you need to sign a release and/or prove you have a license, but I've never had to. You might also consider R152a, which is the new refrigerant slated to replace R134a. At this point, you buy it as "canned air" or "keyboard cleaner" spray, and access the can with a side-tap.

[slofut]

R12 and a PF condensor will definitely make a large difference. It's all about heat exchange. I'd stick with R12, and have accumulated a nice stash from eBay. The listings may say you need to sign a release and/or prove you have a license, but I've never had to. You might also consider R152a, which is the new refrigerant slated to replace R134a. At this point, you buy it as "canned air" or "keyboard cleaner" spray, and access the can with a side-tap.

DW,
Is r152a the propane/butane blend? I think you can buy it in different states for your AC.

[dwcains]

No, and there are quite a few threads available to,read on the various car fora. Here's one that's pretty informative, and a few guys on myE28 and bimmerforums have reported good results, too.

http://www.rx7club.com/1st-gen-archive- ... nt-997918/

Haven't tried it yet, but my system is working well with R12. R152a is about $4/can at Walmart, but I paid about 5x that for the R12 I have. You also only use about 1/2 the weight of R152a.

[Sammy579]

That really was great help.

[JCS]

Fellow Forum members,

I rebuild A/C Compressors, for the BMW Behr/Bosch Wingcell Compressor on the e23,e24,e28,e30,e31,e32 and others.
What is good about is that the Wingcell, it can use either r12 or r134.
These Wingcells after a rebuild, with new seals and bearings, are good for another 30 years.
As they are built so well, the Wingcell features 4 internal bearings around the impeller vane pump.

Please check out my 16 link website below in my footer, and go to # 12.

Best,

[Aaron H]

Jay, where are we to buy the seal kit for the Wing Cell, and where do we get the front seal?

[JCS]

Aaron,

Good Luck

[Aaron H]

Aaron,

Good Luck

No, I just can't believe I'll need any luck. You, yourself said you rebuild these. Along with you, Four Seasons and a handful of other companies are rebuilding these. Seal kits are available. I find it extremely disconcerting that rebuilders are so tight lipped about where they buy their seal kits from. You know that don't make them.

[JCS]

Aaron,

Good Luck

No, I just can't believe I'll need any luck. You, yourself said you rebuild these. Along with you, Four Seasons and a handful of other companies are rebuilding these. Seal kits are available. I find it extremely disconcerting that rebuilders are so tight lipped about where they buy their seal kits from. You know that don't make them.

Aaron,
I make a living doing rebuilds, I will sell you a Wingcell kit for $75.00 to my PayPal it’s my e-mail account [email protected]

[Da_Hose]

Hi Aaron,

Check these guys out. Looks like they might be able to point you in the right direction as well.

https://www.ackits.com/

Here is a good exploded view of a wingcell compressor, with some part numbers you should be able to reference.
https://www.ackits.com/diagrams/Behr.pdf

Check this thread out too. Several of us shared a lot of what we have learned in troubleshooting our AC systems.
http://bigcoupe.com/phpBB2/viewtopic.php?f=2&t=21047

Jose

[tmoretta]

I tested the leaking AC system on my '88 M6 with a leak detector. It pointed to a failed rear evaporator. How difficult to access the evaporator in the between seats rear console and where can I source a new rear evaporator?