The Detailed E30 R-134a Conversion Thread/DIY

[e30 gangsta]

seltec compressor all day.

[Luke_M]

Update on my small problem. Turned out to be a loose electrical connection on the compressor. Duh. Always check the simple things I guess.

I think I have a freezing expansion valve. The most likely reason for this is I used a janky venturi style vacuum pump instead of a traditional vacuum pump. It didn't get a full 29hg, maybe 27-28hg, and after looking at some charts I didn't get close to boiling off the moisture. Most likely the major heat and humidity is causing excess moisture in the system and it freezes up after approx 30 minutes.

[jd_e30]

I'd go with the 4 seasons compressor which I think bolts right in. I can get part number later...

[adjmcloon]

For those of you getting a new compressor, is anybody getting a Sanden? If so, what are you using to mount it?

[jrobie79]

I'm going to be recharging with r12 (grandfather has a boatload in his shed)...however the system was in pieces, will the new pressure switch and dryer still work with r12? i believe the new green o-rings are backwards compatible correct?

also I have to buy a new condensor? would the parallel flow people are finding on amazon or carpart kings not be good if i was keeping r12?

[ParsedOut]

30 below ambient is excellent for a car. You should check for the probe that goes in to the evaporator from just above the gas pedal. Its designed to cut the compressor off when the evap temp gets to 37 to avoid icing. You also should use a 134 exp valve but I wouldnt open an otherwise funcitoning system just to change that

30 below ambient sucks if it's hot out. With 110 ambient, if my A/C blew 80 degrees at me I'd not be happy. My E32 blows 47 degrees while moving and about 55 while idling in 110 ambient. I'd expect the same from a properly converted E30.

Speaking of, my E30 conversion is done but I haven't driven the car since the idle is so rough without tapping into the ECU for idle bump. Don't have the time to dick with it right now and the 735il is more than sufficient right now.

[Luke_M]

I think I have a freezing expansion valve. The most likely reason for this is I used a janky venturi style vacuum pump instead of a traditional vacuum pump. It didn't get a full 29hg, maybe 27-28hg, and after looking at some charts I didn't get close to boiling off the moisture. Most likely the major heat and humidity is causing excess moisture in the system and it freezes up after approx 30 minutes.

30 below ambient is excellent for a car. You should check for the probe that goes in to the evaporator from just above the gas pedal. Its designed to cut the compressor off when the evap temp gets to 37 to avoid icing. You also should use a 134 exp valve but I wouldnt open an otherwise funcitoning system just to change that

[clint-o-matic]

Thanks for this DIY. I ordered all the parts today and will attempt the conversion next weekend.

[jeffnhiscars]

30 below ambient is excellent for a car. You should check for the probe that goes in to the evaporator from just above the gas pedal. Its designed to cut the compressor off when the evap temp gets to 37 to avoid icing. You also should use a 134 exp valve but I wouldnt open an otherwise funcitoning system just to change that

[Luke_M]

I just remembered that I've been hearing a hiss sound from the dash area for the last few weeks. I'm starting to strongly suspect I'm low on freon.

[Luke_M]

He guys. What would cause the system to freeze up? Either the exp valve or evaporator.

Here's my setup:
- '89 325i, 24v swap
- new compressor, new pf condenser and 16" fan, new suction hose and dryer
- replaced all o-rings with the exception of the two on the bottom of the Exp Valve
- kept the old exp valve and pressure switch and all other lines are original
- just added tar like tape to the expansion valve last week.
- It's recently gotten very hot & muggy out
- Confirmed that the fan is working. 16" pusher and 12" puller
- Just checked low side pressure at 60psi at idle, 45psi when revving.
- I see a steady stream of white in the sight glass and the occasional small bubble. I'm told this is normal from an hvac friend of mine.

It was working great for about a month (about 30 below ambient, could use lower but I'm not complaining) but I've recently noticed that it will stop blowing cold after driving for a while. Oddly it will sometimes work fine on the way to a destination and then not work at all when I leave. I'm talking 30 minute drives and an hour or so wait. If I'm doing a lot of sporadic driving around town it will work off and on, mostly off.

I've turned it off once for about 15 minutes, still driving. It came back just fine hence the frozen part suspicion.

Would the tape cause it to freeze over? Or am I leaking freon causing it to freeze over when it gets low?

Picture of the exp valve tape: https://www.dropbox.com/s/4v09nbubv1...613_105125.jpg

[cavpilot]

Finally got around to getting my a/c charged after doing the retrofit as described here. Works great! Thanks glucklich21 for the DIY!

[ParsedOut]

...but it's your car do what you please, just do it in another thread.

I seriously appreciate what you've done here in this thread and talking about a different refrigerant takes nothing away from it. Everything still applies except the R134a. Your attitude on the matter is immature, I guess I'll take my ball and go home.

[cabriodster87]

Yes it's literally computer duster spray cleaner, it's meant to be discharged into the atmosphere.

Be careful with this stuff, for real use good ventilation. Go ask Allison.

[jrockbk]

Still not seeing what's expensive about it. The most costly part is the condenser at $75. Everything else is backwards compatible, except maybe the pressure switch. They may try to tax the crap out of R-134a, but currently there's no legislation to do such a thing with an absolute date listed. So you're fretting over something that may happen in a couple of years which is silly, but it's your car do what you please, just do it in another thread.

Your parts list is over $150 plus $ for doing the labor plus $100 for recharge that's too expensive, only reason I'm in this thread is because I had a legitimate inquiry about the topic and new refrigerant wasn't trying to jack your thread or talk shit about your setup, I was simply saying it's too expensive for my needs, and looking for another alternative, these forums are for these discussions and the hashing out of ideas, don't get butt hurt about my opinions on your setup, FWIW if I had a much nicer car that I didn't plan to sell soon I would totally go this route.