A/C question need help!

[der affe]

i think i am going to mount the new one this weekend (o rings etc, no belt or r134a, then head down to my friends shop and see if he has a parts car i can check out to see where it is on a different year. realoem is of no help as well as the bentley.


another vote for the A/C subfourm?????


thanks for the help though, you are the first person to have any suggestions

[der affe]

bump for anyone else with an idea.

[Tree18is]

it seems to me like you jumped in without knowing very much, The pressure switch is likly an expansion valve an needs to be hooked up somehow, without pressure I belive they stay open letting coolant into the condenser freezeing it. it works off build pressure up, make pressure go down, blow cold air on prick inside.

its been years since ive worked on ac, but thats my .02

[Tree18is]

after looking at the pictures its not an expansion valve.
I would say hook up your system, including the temp switch of course not hooked up to the compressor, but make switch make a look while being hooked up.

if your compressor turns on and off, and your getting cold air leave it, unhook and see what changes.

I know that when I saw a m50 swap done, the e36 compressor was used, along with the wiring harness! so, maybe on the m50 harness they are minus the temp switch.

blah blah blah, google what a temp switch does in an ac system, or read a quick schematic and see whats up, thats what I would do.

[der affe]

it seems to me like you jumped in without knowing very much, The pressure switch is likly an expansion valve an needs to be hooked up somehow, without pressure I belive they stay open letting coolant into the condenser freezeing it. it works off build pressure up, make pressure go down, blow cold air on prick inside.

its been years since ive worked on ac, but thats my .02

it is not a matter of not knowing about a/c, i have that down. i have been doing automotive professionally for a good chunk of my life.
the problem lies in a lack of information. i can't gain any knowledge from either the bentley as to what crosses over or specifics for different years. realoem was a little better, but still not much help.

the rotary comp is a more modern and efficient, with less drag. it is aftermarket, not a factory part. there are kits out there to do the conversion. i now have a good chunk of the kit, i just have to sort a few things out to make it mesh. i was under the assumption that i was not the only one out there that had done this, i guess i was wrong. i knew that is wasn't a pressure switch from searching on realoem. that is where i found out it was a temp switch. mi just need to find out the function and location of it on different years so i can see if i can relocate it or have to have the lines altered to fit it.


thanks for replying though, you are only the second person to do so. i guess noone else knows anything about a/c here, or is unwillling to share ideas

[emi325i]

Do you have a sanden compressor? I put one in may car, I don't recall any issues with the temp switch. The system has a pressure switch at the drier, which I wouldn't bypass. There is a temp sensor on the evaporator inside the dash to prevent icing.

Everything was stock, except for the hoses. I had to pay 300 at a local shop to fab them up. That was a rip-off, they didn't do a very good job, but it works. After all that work, the upgrade was not worth the money. In my non-expert opinion, the condenser is too small for R134A. The e30 condenser is less than 1/2 the size of a modern condenser. So, even though the compressor is efficient, the system has a hard time getting rid of the heat. I wired the aux fan to run on high when the A/C is on, by jumping the hi-temp sensor on the radiator. I also got the windows tinted. It helps.

[der affe]

it is not the sanden. i was looking at the one in the conversion kit. this is a different brand (sorry i don't have it infront of me to give you the name). it is physically longet than the sanden that i was looking at before.

i did the Z-3 condenser fan "upgrade" so i could get maximum air across the condenser for the reason that R134a is not as efficient as R12 (which i have 2 cans of too. ).

i don't know if te tem switch is just redundent or it's actual purpose, that seems to be a stumper.

did your drier have just one pressure switch on it or 2?
if just one, where is your other one located?

do you have a stock oil cooler?
the line for the a/c are directly in the middle of the oil cooler lines on mine. it looks like i will have to disconnect them inorder to tighten them on the comp. if i use the stock ones (they do reach without issue).

i am going to swing by the A/C place and my freinds shop to see if i can get more answers tomarrow.

[emi325i]

it is not the sanden. i was looking at the one in the conversion kit. this is a different brand (sorry i don't have it infront of me to give you the name). it is physically longet than the sanden that i was looking at before.

i did the Z-3 condenser fan "upgrade" so i could get maximum air across the condenser for the reason that R134a is not as efficient as R12 (which i have 2 cans of too. ).

i don't know if te tem switch is just redundent or it's actual purpose, that seems to be a stumper.

did your drier have just one pressure switch on it or 2?
if just one, where is your other one located?

do you have a stock oil cooler?
the line for the a/c are directly in the middle of the oil cooler lines on mine. it looks like i will have to disconnect them inorder to tighten them on the comp. if i use the stock ones (they do reach without issue).

i am going to swing by the A/C place and my freinds shop to see if i can get more answers tomarrow.

There's one switch on the drier and a temp probe on the evaporator. The oil cooler lines were in the way; you can bent them a little bit by hand, but not much. You could take them out and bent them properly; put a decent radius in the bend, so it doesn't kink.

[der affe]

alright i got the scoop on the A/C problems.

1. the temp sensor is NOT NEEDED, infact if you look at the 3 prong connector, the wire inside just makes a loop. so it is going away. all you need is the power switch for the clutch.

2. just bend the oil line out of the way, no problem. i have a tubing bender so i will put some nice bends in it and solve the problem.

3.when you do the rotory or a 134A conversion it will blow the coolest if you UNDERFILL it just a little 1.8 lbs seems to be the magic number, as opposed to the 2.0-2.2lbs. this seems to work best because the small size of the condenser.

4. if you can't get the a/c to work by moving the middle slider over on the climate control, remove the radio and reach down just to the left of center on the back side of the slider and remove the wires that go to the slider circuit board. then crimp cap them together or take a scotch tap and loop them. this will bypass the circuit board (this was a factory TSB from back in the day) your A/C will still work with the switch, but you wont need the middle slider to let the a/c work.


i will take a bunch of pics and do an install thread sine noone has done this themselves yet it seems.

[E30stan]

alright i got the scoop on the A/C problems.

1. the temp sensor is NOT NEEDED, infact if you look at the 3 prong connector, the wire inside just makes a loop. so it is going away. all you need is the power switch for the clutch.

2. just bend the oil line out of the way, no problem. i have a tubing bender so i will put some nice bends in it and solve the problem.

3.when you do the rotory or a 134A conversion it will blow the coolest if you UNDERFILL it just a little 1.8 lbs seems to be the magic number, as opposed to the 2.0-2.2lbs. this seems to work best because the small size of the condenser.

4. if you can't get the a/c to work by moving the middle slider over on the climate control, remove the radio and reach down just to the left of center on the back side of the slider and remove the wires that go to the slider circuit board. then crimp cap them together or take a scotch tap and loop them. this will bypass the circuit board (this was a factory TSB from back in the day) your A/C will still work with the switch, but you wont need the middle slider to let the a/c work.


i will take a bunch of pics and do an install thread sine noone has done this themselves yet it seems.

awaiting install thread