Coverting R12 to R134, who's happy?

[Eric Giles]

Even though I recommend sticking with r12 if possible, I do have to mention one issue-all of the new expansion valves that are available are listed as r134a/r12 compatible. No one makes an r12 specific expansion valve any longer. Now the r134a valve will work, however-the r134a valve has (from what I was told from a member on E30tech) a physically smaller valve opening that is optimized for r134a use. Because of this, at idle even r12 will no longer cool that well until you are driving. This was explained to the E30tech member by an a/c tech that supposedly knows his stuff.

i have personally experienced it in the last two E30's that I have performed a/c work on which used the r134a valve. Now my '88 M3 has an r12 specific valve that was still available back in '06 when I reworked it's a/c system and it works perfectly at all speeds-even idle. I was never able to understand why the other E30's didn't perform optimally at idle compared to the M3 until I read about the expansion valve issue.

My advice if you are going to stick with r12 is to clean and re-use your original r12 expansion valve. There is a writeup on E30tech.com that explains how to properly 'refurbish' your original valve-and I wish I had known about all this before I threw my last original r12 valve away.

[91 318is]

Is there a good source for an R12 substitute online? I'm having problems finding it. If only I could find a shop that could evac my system and save the R12 while I modify the lines...

http://www.freeze12.com/

Guess I'll be sticking with R12, I like my A/C ice cold.

[nrubenstein]

The issue is that the condenser is not physically large enough to handle R134a really well. I've dramatically increased the airflow through mine, which makes it work a lot better, but the root of the problem is that the E30 had a sketchy condenser for R12, and it's pretty overworked with R134a.

[PУCCKAЯ_e30ka]

what if you have new comprs/drier/switch/evap?
I would think r134 would be as good as r12?

[gearheadE30]

Is there a good source for an R12 substitute online? I'm having problems finding it. If only I could find a shop that could evac my system and save the R12 while I modify the lines...

[xphiledan]

I just converted to R134, and I'm very happy with it.

[THE FEZMAN]

stick with r 12 or freeze 12

[PorkandBeans]

Change the fuse to 30 amps and bypass the resistor. You can splice the low wire to the high, or you can jump a wire across. It's very easy, and it makes the ac work a LOT better.

I was just about to do this, tracking down a new resistor is pointless. Thanks for the confirmation. Fuse 3, right?

[nrubenstein]

How did you do this? My low speed resistor is out and my car never gets hot enough to kick the aux fan on high speed. I want it on high at all times the A/C/ is on. Do I just remove the resistor entirely?

Change the fuse to 30 amps and bypass the resistor. You can splice the low wire to the high, or you can jump a wire across. It's very easy, and it makes the ac work a LOT better.

[PorkandBeans]

With the aid fan rigged to high, R134a works fairly well in my car.

How did you do this? My low speed resistor is out and my car never gets hot enough to kick the aux fan on high speed. I want it on high at all times the A/C/ is on. Do I just remove the resistor entirely?

[91 318is]

Hmmm, are there any R12 substitutes at local parts stores like advance auto or NAPA? Or do I need to order Freeze 12 online? I don't think I have any leaks because the A/C works, it's just not very cold.

[hoveringuy]

The problem with R134 in these cars is that the condenser and evaporator aren't large enough for effective cooling. The system will work, it just won't cool nearly as well with R134 as with R12. I've seen a couple of conversions using R12 replacements (e.g. Freeze12 or similar) that worked much better than R134. That said if your system isn't leaky, it would make sense to retain the R12 until the system needs works and the R12 has to be dumped..

+1.

I lived in Maryland and ran Duracool (same as Freeze12). Car blew cold air unless I was stuck in really miserable beltway traffic.

R134 didn't cut it. Condensor is just too small!

Stick with R12 if possible.

[Tbolt]

http://www.amazon.com/gp/product/B00...2S39CF83A4YQT5

will this work with e30s?

would i need anything else?

[evil_twin]

Im looking for Freeze12 and I can't find it anywhere. I would love to put Freeze12 in my system, but R134 is just so much easier to find.

[KenC]

I'd do whatever you can to get the R-12. You're only recharging it once every 5+ years, so the "convenience" of the r134a availability is really moot.