Coverting R12 to R134, who's happy?

[torqueflight]

I put r134 in my r12 system because Im lazy, but it works. I just have to find the leak. That leak stop doesn't really work well. So far its been working for over a year and half. Im thinking of cleaning the system out and going with the freeze 12.

[Jean]

It's on the fan - and cooled by it. 85W, .5 ohm, IIRC. I'm planning on stepping up to an aftermarket fan controller, some day. For now, I just tossed a few old sealed beams into the battery tray, wired them up in parallel, and called them a low speed resistor.

WAY cheaper than a new resistor at dealer / e-tailer prices.

instant/permanent engine bay light :)

But seriously, hit up a local electronics store, and you'll find a resistor of enough wattage and same resistance for a few bucks.

[clavinZERO]

You know it's funny you say that because I found out today my aux fan isn't working, so I gotta fix that now. The A/C seemed to work decent when I'm riding down the highway, but as soon as I stopped, it would get warmer. Found out my fan isn't working.


Since we're on the subject, where is this resistor located?

The resistor should be on bottom of fan, as you face it while standing in front of the car. It has a fat wire with a terminal screwed onto it on both the "in" and "out" sides. About $20-25 to replace.

[u3b3rg33k]

It's on the fan - and cooled by it. 85W, .5 ohm, IIRC. I'm planning on stepping up to an aftermarket fan controller, some day. For now, I just tossed a few old sealed beams into the battery tray, wired them up in parallel, and called them a low speed resistor.

WAY cheaper than a new resistor at dealer / e-tailer prices.

[91 318is]

A few years ago, after my a/c system was wide open, I put in r134a. I installed a new receiver/drier and new o-rings at the reachable fittings. The compressor was my original from 1990. I added the update valves for the r134a and dropped some of that esther resin stuff that is supposed to lubricate the system or something (read the label for amounts, etc.). The system was then vacuumed down and recharged with the r134a. At idle this did not work as well as r12, but during cruising of any speed it blew 36/37 degrees through the vents on pretty warm days; I had a thermometer shoved into the dash vents to test the refreshed system.

Helpful hint: make sure both the speeds work on the auxilliary fan!! My resistor broke (for the low speed) and one day the a/c line blew a hole near the exhaust manifold. I am assuming this happened because the lack of cooling overheated the system and built up too much pressure.

You know it's funny you say that because I found out today my aux fan isn't working, so I gotta fix that now. The A/C seemed to work decent when I'm riding down the highway, but as soon as I stopped, it would get warmer. Found out my fan isn't working.


Since we're on the subject, where is this resistor located?

[u3b3rg33k]

A few notes

I like to use something hydrocarbon based, ie R12a; I like duracool, and it's very effective, not to mention cheap (30lbs for under $190). HC refrigerants will accept M1 0w30 as lubrication, and be perfectly happy. R134a will not. Also, R134a is a horrible greenhouse gas. The CARB claims it's 1300x worse than CO2.

A working aux fan is an absolute must, regardless of what refrigerant you choose. the system creates a temperature differential between the condenser and the evaporator. the cooler you keep the condenser, the happier you'll be.

[clavinZERO]

A few years ago, after my a/c system was wide open, I put in r134a. I installed a new receiver/drier and new o-rings at the reachable fittings. The compressor was my original from 1990. I added the update valves for the r134a and dropped some of that esther resin stuff that is supposed to lubricate the system or something (read the label for amounts, etc.). The system was then vacuumed down and recharged with the r134a. At idle this did not work as well as r12, but during cruising of any speed it blew 36/37 degrees through the vents on pretty warm days; I had a thermometer shoved into the dash vents to test the refreshed system.

Helpful hint: make sure both the speeds work on the auxilliary fan!! My resistor broke (for the low speed) and one day the a/c line blew a hole near the exhaust manifold. I am assuming this happened because the lack of cooling overheated the system and built up too much pressure.

[91 318is]

might be bit of a noob question, but how can I tell if my car has been converted or not?
It's had 2 previous owners that took good care of the car for the most part.
Any help is appreciated, thanks

The service fittings are different on each. R12 has screw on service fittings and R134A has quick disconnect fittings.

I ended up servicing the system with R12, I couldn't find a pressure chart and I didn't want to completely evacuate the system. I ended up getting 40 on low & 250 on high. When I first hooked up, I had 30 on low and 180 on high.

Still doesnt blow that cold.

I may just evacuate the system and convert it over unless someone has a better option.

[movementality]

might be bit of a noob question, but how can I tell if my car has been converted or not?
It's had 2 previous owners that took good care of the car for the most part.
Any help is appreciated, thanks

[///M42 sport]

mine works fine. I have bothh R12 and R134 in my system

[91 318is]

Does anyone know what the recommended head pressures are suppose to be for R12? I know R134A is gonna be higher then R12. I searched google and got nothing.

I'm gonna try and charge it today and see what happens.

[619E30]

Mine runs on r12 and I just recharge it with freeze 12, way easier

[fliplap]

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

I too converted to r134a, 3 years ago. It was 113F out the other day and I was perfectly cool.

[Eric Giles]

Good info right here. Since I was sticking with R12, I was just gonna service the system and let it go. Should I completely evacuate it and clean the expansion valve?

Since you don't think you have any leaks and the system is still somewhat operating, I would just have a shop fill it with the proper amount of r12 for now and see how it works. No o-ring replacement or evacuation-just recharge and see what happens.

[91 318is]

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.

Good info right here. Since I was sticking with R12, I was just gonna service the system and let it go. Should I completely evacuate it and clean the expansion valve?