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A/C R12 to R134a using Sanden Compressor with stock M20 oil cooler lines

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    A/C R12 to R134a using Sanden Compressor with stock M20 oil cooler lines

    I just recently retrofitted a R134a Sanden A/C compressor into my '89 325i M20 with stock Oil Cooler lines. There is a bit of modification in order to make this work. But at the end- you will have a 100% R134a setup. There is a lot of broken information out there on the Sanden in the M20- threads started but never followed up with how it was done. Here is my contribution to the community...

    First off- Big kudo's to Glucklich21's DIY on the conversion. There is a bunch of good info on his thread and a very nice writeup.
    http://www.r3vlimited.com/board/showthread.php?t=246743

    I found a Sanden R134a compressor out of a '91 e30 vert. I'm not sure if this was originally converted from r12 or was r134a from the factory. If you cannot find a used Sanden- they can be obtained NEW (not remanufactured) for under $200 on ebay. As mentioned before and in other threads- Sanden is an overall awesome compressor and is specifically made for r134a. Hearing the great reviews on it and rather than retrofitting my R12 Bosch, I decided to use it. It is super quiet and doesn't hog a lot of crank power.

    Unfortunately, the mounting bracket that the Sanden uses is different than the stock R12 AC mount. I had to extensively modify the Sanden bracket to work. The mounting holes are the same on the block, but the CPS bracket and an ear on the block are in the way. Ended up using my Dremel and a grinding disk to make clearance on the bracket- along with grinding down the CPS bracket a bit.

    This is what the Sanden bracket looks like (thanks member R3v Boris3)


    You can try to make a bracket if you're up for the challenge:
    http://www.bimmerforums.com/forum/sh...ressor-install

    Then the Sanden IN/OUT fittings are in the rear of the unit- not in the center like the Bosh or OEM units. If you have a 325i or M20 with an oil cooler- you will have to modify your lines. No way around this- as the low pressure hose CAN fit- but rubs against the exhaust manifold/oil cooler lines.

    I ended up getting mine re-done with barrier hoses. I added a hose from the front high pressure union to the compressor union (added about 5 inches in length for the curvature- removed the hard line sections and added two straight hose fittings to both ends. I would do a bend, something less than 90 Degrees for the condenser fitting) For the low pressure side, I had it shortened by 3 inches with a barrier hose. While the high pressure hose worked out perfectly, I should have removed only 2.5 or 2 inches from the low pressure hose, as it is a little too short and I need to figure out a good house mounting bracket- as in my pictures it is zip tied to the dizzy coil. I ended up having enough wiggle room to route them through the oil cooler lines. Wrapped them with exhaust wrap since I didn't want the rubber to get too hot and melt.

    Vac'd my system down to 22mmHg with my crappy 5hp 20gal compressor for a good hour, added new PAG oil, a new parallel flow condenser from Amazon (the one pictured a few times in the R134a conversion thread) new aux fa wired to LOW, R134a expansion valve, new dryer with one pressure switch (modified from two switches) and of course new O-Rings.

    Two pressure switch to One pressure switch wiring (the only straight forward way on the interwebs to wire this- the BMW TSB doesn't help out too well)
    http://www.r3vlimited.com/board/showthread.php?t=342398

    Blowing out a nice crisp 28 Degrees at idle on a 86 degree day at 50% humidity. The Sanden compressor is quiet as hell, can't even tell it is on (but it is!) It was a overall a giant pain in the butt project- but thankfully I didn't have any leaks or issues after getting everything squared away.



    Sanden Bracket- modified


    Routing of the AC lines through the oil cooler lines. I wrapped them with exhaust wrap I had laying around since I didn't want the rubber to melt being that close to the exhaust manifold.



    The only pics I took of the modified lines. The high pressure side has that same fitting on both ends and only a rubber hose in-between (no hard lines)


    PF condenser and new aux fan
    555Garage - Kingston, PA

    '13 BMW e70 X5 35d
    '95 BMW e34 525i
    '92 BMW e30 325i S52 Vert (Quade the Vert)
    '92 Range Rover Classic
    '90 Range Rover Classic
    '89 BMW e30 325i Coupe (The DIRTY30)
    '81 VW MK1 Rabbit Caddy Diesel
    '76 Honda CB550K Cafe/Brat
    '67 Pontiac LeMans
    '24 Model T Depot Hack
    ....And a bunch of Motobecane, Puch, Garelli, Batavus and Honda 49cc-78cc Mopeds...


    #2
    Based on the that reading you obviously got the job done very well. Fyi the evaporator temp probe, which I hope you reinstalled , is set to turn the compressor off at 37degree to prevent icing
    Deck Lid and soft top Shocks on hand

    Seat shocks on hand for immediate shipment
    https://www.r3vlimited.com/board/sho...86#post4944786
    Alice the Time Capsule
    http://www.r3vlimited.com/board/showthread.php?t=360504
    87 Zinno Cabrio barn find 98k and still smells like a barn. Build thread http://www.r3vlimited.com/board/show...20#post3455220

    Comment


      #3
      Originally posted by jeffnhiscars View Post
      Based on the that reading you obviously got the job done very well. Fyi the evaporator temp probe, which I hope you reinstalled , is set to turn the compressor off at 37degree to prevent icing
      So the only thing I did not touch was the evaporator and the temp probe. It's all still installed. I was pretty surprised that the aux fan kicked on when hooking it up. Before I ripped out all my original AC gear- the aux fan wouldn't power up and I was afraid that I would have some sort of electrical issue to deal with. Fortunately for me- the old dryer switch wiring was all foobarred and that was the issue for no power to my old compressor.

      I did blow air into the evap unit to clean it out a bit but didn't remove it.
      555Garage - Kingston, PA

      '13 BMW e70 X5 35d
      '95 BMW e34 525i
      '92 BMW e30 325i S52 Vert (Quade the Vert)
      '92 Range Rover Classic
      '90 Range Rover Classic
      '89 BMW e30 325i Coupe (The DIRTY30)
      '81 VW MK1 Rabbit Caddy Diesel
      '76 Honda CB550K Cafe/Brat
      '67 Pontiac LeMans
      '24 Model T Depot Hack
      ....And a bunch of Motobecane, Puch, Garelli, Batavus and Honda 49cc-78cc Mopeds...

      Comment


        #4
        Thanks for the write up. I've been researching as I need to get the AC working again. What model of compressor did you buy?

        Comment


          #5
          Nice job! I'm glad everything worked out for you. I had no idea those compressors were so much different and its good to see you modified accordingly. Your system is definitely running a lot better than mine. I too followed that conversion write up, but my compressor just gave out. I'm not sure why, but I just used what I had. Will be swapping in another one this weekend. Hopefully I'll get tempatures like that as well.

          Could I ask how much refrigerant you ended up having to put in the system total? And how much oil is your compressor recommended to use?

          Could you also go into detail on the filling process? If you did it yourself...
          I don't even own this car anymore, but I'm too lazy to change the picture.

          Comment


            #6
            Originally posted by spike68 View Post
            Nice job! I'm glad everything worked out for you. I had no idea those compressors were so much different and its good to see you modified accordingly. Your system is definitely running a lot better than mine. I too followed that conversion write up, but my compressor just gave out. I'm not sure why, but I just used what I had. Will be swapping in another one this weekend. Hopefully I'll get tempatures like that as well.

            Could I ask how much refrigerant you ended up having to put in the system total? And how much oil is your compressor recommended to use?

            Could you also go into detail on the filling process? If you did it yourself...
            Spike, are you using the stock Bosch R12 unit for the conversion? I'm trying to figure out which compressor to buy for my update to R134a.

            Thanks!

            Comment


              #7
              Originally posted by Cephas View Post
              Spike, are you using the stock Bosch R12 unit for the conversion? I'm trying to figure out which compressor to buy for my update to R134a.

              Thanks!

              I am not. Mine is a Denso (technically called Nippondenso). One I may be swapping out for this weekend is a Seiko. I have another but I'm not sure what kind it is. I'll just choose which I think is in better condition when I get there.

              Refer to the following list for conversion compatibility and required oil:

              https://docs.google.com/file/d/0B6qM...t?pref=2&pli=1

              Yours is on there. Not sure if yours is rotary or oscillating, but they're both on there. This list was pulled from the conversion thread that was originally referred to by Klug.
              I don't even own this car anymore, but I'm too lazy to change the picture.

              Comment


                #8
                Originally posted by spike68 View Post
                I am not. Mine is a Denso (technically called Nippondenso). One I may be swapping out for this weekend is a Seiko. I have another but I'm not sure what kind it is. I'll just choose which I think is in better condition when I get there.

                Refer to the following list for conversion compatibility and required oil:

                https://docs.google.com/file/d/0B6qM...t?pref=2&pli=1

                Yours is on there. Not sure if yours is rotary or oscillating, but they're both on there. This list was pulled from the conversion thread that was originally referred to by Klug.

                Thanks. Did you have to fabricate a bracket or buy one somewhere? I have my original compressor, but it has been disconnected from the car for years and sitting in the PO's garage/my shed for probably a decade. I'm not going to reuse it, so I'll buy a new one from that list. My big headache is trying to find out if any aftermarket compressors will fit with the stock bracket.

                Comment


                  #9
                  Originally posted by Cephas View Post
                  Thanks. Did you have to fabricate a bracket or buy one somewhere? I have my original compressor, but it has been disconnected from the car for years and sitting in the PO's garage/my shed for probably a decade. I'm not going to reuse it, so I'll buy a new one from that list. My big headache is trying to find out if any aftermarket compressors will fit with the stock bracket.

                  My compressor I am running now was off my vert so I grabbed the bracket as well. It has been on the car not working for over a decade as well. I didnt even know if it would work, but I gave it a shot because its not as if the compressor was engaging for that many years since the switch cuts it off if there is no refrigerant. Most OEM brackets are the same when mounting to the block, but are varied when interchanging compressors with brackets. If you source a compressor try your best to get the bracket with it as well to make things easier.

                  As far as aftermarket compressors go I am not really sure but there are plenty of OEM compressors from e30s that work just fine so if it were me i'd just stick with that. Getting new compressors are expensive OEM or aftermarket. Youd probably have better luck sourcing one from a member here since its way cheaper.




                  Sorry Klug for kinda hijacking....
                  I don't even own this car anymore, but I'm too lazy to change the picture.

                  Comment


                    #10
                    You guys are right about mounting brackets for aftermarket compressors. APG no longer makes them so you are limited to either fabbing one or staying with a stock compressor.

                    The caution with stock compressors is a) they are designed to work at r12 pressures but can still perform admirably and b) only certain ones have seals that are r134a compatible. That's the real risk.
                    Deck Lid and soft top Shocks on hand

                    Seat shocks on hand for immediate shipment
                    https://www.r3vlimited.com/board/sho...86#post4944786
                    Alice the Time Capsule
                    http://www.r3vlimited.com/board/showthread.php?t=360504
                    87 Zinno Cabrio barn find 98k and still smells like a barn. Build thread http://www.r3vlimited.com/board/show...20#post3455220

                    Comment


                      #11
                      Thanks Jeff. The compressor from my car has been sitting uninstalled for years. Going to get a new one from autozone for $215 all said and done instead of rolling the dice on the original. I know it used to work, but I think sitting unhooked amd unused for so many years makes it too big of a risk.

                      Comment


                        #12
                        So 116F kinda sucks, it might be time to get the A/C back up to speed

                        Ok so what’s the latest on new compressors for an M20? i want a good R134a version to get my A/C back up to speed

                        I’ve noticed that places that sell OE compressors have two p/N x 64528391152 (post 3/1992) and 64528385712 (upto 1992) what is the actual difference? ts my understanding these are not “true” R134a compressors, they are just modified to compatible so the ridiculous pricing isn’t even justified?

                        The sanden one sounds like the go being a more modern type (quiet, efficient etc) but i want a new one is there a specific part number to look for that is pretty close to PNP ? Do they come with a bracket? I’m ok with modifying a bracket slighty but new lines sounds like a pita especially with headers and oil cooler etc
                        89 E30 325is Lachs Silber - currently M20B31, M20B33 in the works, stroked to the hilt...

                        new build thread http://www.r3vlimited.com/board/showthread.php?t=317505

                        Comment


                          #13
                          Bmw didn't ship e30s w r134 until very late in the production run and I'm not sure what compressor they used since they shipped a lot of cars that were "r134 compatible" which means they had updated seals but still were designed for r12

                          I've installed r134 specific compressors from both sanded (the 507) on the M10 and seltec on the M20. They are both good "modern" r134'specific units but the challenge is mounting.
                          Last edited by jeffnhiscars; 05-13-2017, 05:50 AM.
                          Deck Lid and soft top Shocks on hand

                          Seat shocks on hand for immediate shipment
                          https://www.r3vlimited.com/board/sho...86#post4944786
                          Alice the Time Capsule
                          http://www.r3vlimited.com/board/showthread.php?t=360504
                          87 Zinno Cabrio barn find 98k and still smells like a barn. Build thread http://www.r3vlimited.com/board/show...20#post3455220

                          Comment


                            #14
                            i assume Seltec is aftermarket ? what p/n requires least mods to fit to m20 ? if you know)

                            Do you think p/n 64528391152 is a proper r134 specific compressor ?
                            89 E30 325is Lachs Silber - currently M20B31, M20B33 in the works, stroked to the hilt...

                            new build thread http://www.r3vlimited.com/board/showthread.php?t=317505

                            Comment


                              #15
                              Valeo owns seltec and although to my knowledge they have never been an OE supplier of compressors they are a highly reputable brand. Having said that, keep in mind that like many other mfgs, they do have Chinese production. I made sure mine was made in Japan.

                              Again, I am not awar of BMW ever selling an e30 with an r134 specific compressor. Rather they are all "compatible" (meaning the seals will stand up). For the real deal you will need to go aftermark. If you check my cabrio build thread there should be specifics on the seltec model. I orderd one with an aluminum end cap cause I thought I was going to use hoses with aluminum ferrules. The one speced for the bracket I boughtnhad steel hose connections. This is all in the name of having similar metals to limit corrosion but is not a major concern in a salt free environment.

                              Mounting is your big limit but for someone who has fabbed more exhausts than anyone I know you should be able to sort that part out.
                              Deck Lid and soft top Shocks on hand

                              Seat shocks on hand for immediate shipment
                              https://www.r3vlimited.com/board/sho...86#post4944786
                              Alice the Time Capsule
                              http://www.r3vlimited.com/board/showthread.php?t=360504
                              87 Zinno Cabrio barn find 98k and still smells like a barn. Build thread http://www.r3vlimited.com/board/show...20#post3455220

                              Comment

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