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The Detailed E30 R-134a Conversion Thread/DIY

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    does anyone have a link to a forum post, or know themselves how to test an old compressor to see if it needs replacing? I want to do this retrofit to my 87 325is, I bought the car last summer and have never had a belt on my A/C compressor, the PO said he never had A/C nor tried to get it to work. So I am just wondering how I can see if my existing compressor is up to the job or if I should replace it. I know its probably better to just replace it, but trying to save $$ anyway I can on this job, and if it doesn't need replacing, I would like to use the part I have.
    87' 325is For Sale

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      Originally posted by e30325is603 View Post
      does anyone have a link to a forum post, or know themselves how to test an old compressor to see if it needs replacing? I want to do this retrofit to my 87 325is, I bought the car last summer and have never had a belt on my A/C compressor, the PO said he never had A/C nor tried to get it to work. So I am just wondering how I can see if my existing compressor is up to the job or if I should replace it. I know its probably better to just replace it, but trying to save $$ anyway I can on this job, and if it doesn't need replacing, I would like to use the part I have.
      Do yourself a favor and just replace it. Especially if you are converting since you are doing a lot of work and compressors lock up in the worst places.
      1989 Cirrus Blau coupe Racing Dynamics wheels and a Volvo Spoiler.

      Comment


        I appreciate all the hard work that has been put in by R3V's into this guide and discussion.

        My question is for those that have a stock AC compressor for the M20 engine, does replacing the condenser with a parallel flow and having a properly operating electric fan allow you to get good vent temperatures when stationary in traffic assuming a good TXV, evaporator and compressor?

        I'm not sure I want to go the Sanden / Seltic path and try to find the associated expensive mounting kit. if I go through the effort to replace the condnenser, evaporator and TXV, and associated lines I would like to know that I can expect satisfactory, at least cold air. At idle is it the condenser or the stock compressor the limiting component?
        You replies would be appreciated.

        Comment


          My opinion would be "no".

          I now have a parallel flow condenser that is appx. 30% larger with a Sanden compressor and a huge SPAL fan. My vent temps aren't much better. Why? I think it's the expansion valve. While marketed as 134a compatible, I believe they are R12 and thus not flowing enough refrigerant to the evaporator.

          Eventually, my last ditch effort to try to polish this turd of an AC system will be to make custom hoses to use an office tube. And then we shall see.

          Anybody already tried this?

          Comment


            I just finished up my s54 swap and decided I want to add A/C searched and found this thread, thank you OP for this!
            sigpic
            E30love

            Comment


              I'm getting great vent temps with a 24v setup, parallel flow cond, but stock expansion valve, evaporator and even stock pressure switches.

              I had a custom line that let go and before that my vent temps were so-so. They improved a lot after I got the pusher fans blades facing the correct way (improved efficiency) and pulled a really good vacuum. That seemed to make a difference for me anyway. Of course you need to get the freon levels just right but I filled it the same way I did the first time and only got decent results originally.

              The vent temps are only 1-2 degrees off my gf's vw jetta which has the coldest ac ever. That seems acceptable to me.

              A/C systems seem to be finicky but it can be done!
              Euro S50 Daily Driver: http://www.r3vlimited.com/board/showthread.php?t=279195

              Comment


                Just chiming in now after overhauling my AC the past few weeks.

                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. Anyway- 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.

                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, 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.

                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. 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. I ended up having enough wiggle room to route them through the oil cooler lines.

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

                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
                Last edited by Klug; 06-07-2015, 09:21 AM.
                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


                  Not so great to have the evaporator that cold, especially on a humid day, as it will have a tendency to ice up.

                  Comment


                    I have a 1991 325i ragtop where the R12 has finally all leaked out (or at least R12 levels low enough to not function). Because I have a good supply of '80s vintage R12 cans, I'm planning to replace the condensor with a parallel unit, dryer, and all the o-rings I can get to. Add an ounce or two of R12 oil to the replaced components, then vacuum test. I pulled a hard vacuum on my prior car when converting to R134 via this DIY and that system blew ice cold when done. In this case, I'm keeping it R12 so I don't have to mess around under the glove box. Will also buy a leak detector per previous posts. The compressor is quiet, but of course no way to tell if the seals leak without refrigerant in the system. Any other considerations I should be thinking about? And as said before, kudos to the OP - I wouldn't have tried my last retrofit without the DIY.
                    "If the sky were to fall tomorrow, the tall would die first."

                    -Dr. Paul Forrester



                    Do I LOOK like I need a psychological evaluation???

                    Comment


                      A/C hard line connections

                      Hi, I've posted this elsewhere with very little response....

                      Can anyone share their experience regarding the A/C hard lines along the passenger front fender? There are two connections there, behind the hood latch, and I'm curious if they have o-rings, or crush washers, flares, or?

                      Realoem shows nothing but I don't necessarily believe that. http://www.realoem.com/bmw/enUS/show...diagId=64_0529

                      If there IS nothing, or crush washers, or flares, I want to leave them alone. If there are o-rings, I want to get in and replace them.

                      Thanks!
                      Attached Files

                      Comment


                        Originally posted by GoldMember View Post
                        Hi, I've posted this elsewhere with very little response....

                        Can anyone share their experience regarding the A/C hard lines along the passenger front fender? There are two connections there, behind the hood latch, and I'm curious if they have o-rings, or crush washers, flares, or?

                        Realoem shows nothing but I don't necessarily believe that. http://www.realoem.com/bmw/enUS/show...diagId=64_0529

                        If there IS nothing, or crush washers, or flares, I want to leave them alone. If there are o-rings, I want to get in and replace them.

                        Thanks!
                        O-Rings
                        1991 318is ---230K - DD
                        1991 318i ---- 308K - retired

                        Originally posted by RickSloan
                        so if you didnt get it like that did you glue fuzzy oil to the entire thing?

                        Comment


                          Originally posted by GoldMember View Post
                          Hi, I've posted this elsewhere with very little response....

                          Can anyone share their experience regarding the A/C hard lines along the passenger front fender? There are two connections there, behind the hood latch, and I'm curious if they have o-rings, or crush washers, flares, or?

                          Realoem shows nothing but I don't necessarily believe that.

                          If there IS nothing, or crush washers, or flares, I want to leave them alone. If there are o-rings, I want to get in and replace them.

                          Thanks!
                          Mine had o-rings. I'd bet yours do too.

                          Comment


                            Thanks guys, for the response.

                            I had someone on another forum say there were nylon bushings in there. O-rings sounds more like what I'd expect.

                            Comment


                              Originally posted by GoldMember View Post
                              Thanks guys, for the response.

                              I had someone on another forum say there were nylon bushings in there. O-rings sounds more like what I'd expect.
                              You can pretty much account for any A/C hose union having O-rings between them.

                              Condenser - 2
                              Dryer - 2 + # of switches you have
                              Compressor - 2
                              Firewall/Cabin - 2
                              Evap Valve - 4

                              So I'm counting 12 total off the top of my head, plus 1 or 2 more depending on the switches you have on your dryer.
                              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


                                I tried to pull the firewall connections apart yesterday and gave up thinking I was going to break something or just round off the flats of the hexes. Super tight. :( I was using the proper size wrenches and even resorted to a vice grip to no avail. I ran that system with R134a for 5 years and it didn't leak so I think (hope) I'm safe with leaving those connections alone as I plan to install R12.

                                Everything else is going well. I'm about to install my new (reman) compressor and finally the drier.

                                Thanks.
                                Last edited by GoldMember; 06-19-2015, 08:25 AM.

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