The Detailed E30 R-134a Conversion Thread/DIY

[glucklich21]

just finished charging my system after installing the new parts. This is the coldest AC EVER!

At idle my vent temp is 36 degrees.

Glad to hear you're happy with it! :)

[DIIRTY-30]

Future project indefinitely, great write up!

[BlackbirdM3]

So how much of this is different on an M3, specifically one built 10/87? My A/C doesn't work, however everything seems to function. My guess is that the R12 all leaked out from somewhere, but I don't know for sure. It might just be a bad pressure switch, I don't know. I do know that when I push the a/c button the fan kicks on, the compressor starts running but I never hear the click of any pressure valves opening or closing, and it never gets even remotely cold. The previous owner had the system recharged in November of 2011, but that was when the car was still in Canada. Its hard to tell if the a/c system is working when the outside temp is 32 degrees. I'd love to get this fixed, but I'm told there are a few things different on the M3.


Will

[Dj Buttchug]

youre going to have to cross part numbers. The compressor is different so Its going to require different oil. I would assume some or most of the hardline o rings are the same, aside from the hardline shapes and routing. The condenser could be different but again, realoem that one out. Pretty sure the expansion valve is the same.

[KAR]

*Bump*
I'm in Houston, TX and this DIY looks like just what the doctor ordered. Please sticky!

[Mad Chemist]

Anybody have the TIS on how to use the newer dryer with one sensor port versus the older version with two. Just want to make sure I am doing it right but I can't find the damn TIS again. Thanks.

[ELVA164]

http://www.pelicanparts.com/cgi-bin/...abel%2C%20Each

Do the o-rings in this package match the part numbers provided in OP? I can't find any part number lists on pelican parts' site.

Also, how can you check if an evaporator is good? My A/C system has never worked since I've owned the car (bad compressor) and I want to make sure it isn't the weak link.

Really excited to get this going...

[Fleksta]

Does anyone have another link to the PAG oil chart? The one in the OP has been linked to a "store under maintenance, back in an hour" page for at least a week now.

[Click]

[e30jr88]

Does anyone know if some of the compressors come pre-oiled?

I redid my AC system about 8 months ago and I didn't add any oil since I noticed there was some oil when I gave it some revs by hand. Therefore I decided to just install it and fill it. Just last week the compressor has started to squeal pretty loud upon initial start after sometime(few mins of driving on the road) the noise goes away.

Am I going to have to open it up, oil and refill or could there be a different issue that is causing the squealing? (the belt is on tight but not sure how old the idler puller is)

[jeffnhiscars]

I just installed a Seltec with a factory tag that says 150cc of oil, but the vendor included a slip that says "check" to CYA. I did check and there was oil in it, but that doesnt mean every mfg prefills them. My guess would be that if you installed an empty compressor you would have had an issue right away so presumably your squeal is just the pig you ran over :-)

[e30jr88]

I just installed a Seltec with a factory tag that says 250cc of oil, but the vendor included a slip that says "check" to CYA. I did check and there was oil in it, but that doesnt mean every mfg prefills them. My guess would be that if you installed an empty compressor you would have had an issue right away so presumably your squeal is just the pig you ran over :-)

haha I know Its been a few months, the AC works fine as well not as cold as it was with my old compressor(R12 fluid) but still helps some. I'm going to try to remove the AC belt and make sure the noise isn't coming from anywhere else. Been debating about upgrading to a parallel condenser anyway so might open it up in the near future.

[jeffnhiscars]

It occurs to me that the chart with compressor oil capacities may not be quite accurate. My Seltec TM had 150cc in it out of the box which was factory stamped on the ID plate. Since this is just over 5 oz I'd say that chart represents system capacity not just the compressor. I added oil to the new components according to several sources including Bentley for a total of about 7-7.5oz. They also say to add oil when you replace components, I assume to replace residual oil that you remove with the old component.

I also used the factory service bulletin as a performance guide as far as high\low pressures. ambient temp, humidity and vent temps until I realized they were written for retrofits, meaning compressors designed for r12 which operate at a lower head pressure than is optimum for r134a. Since my new compressor was designed for r134a the chart is interesting, but essentially useless.

This was confirmed by putting gauges to my white cabrio which has been retrofitted with the original compressor, pumps 37 degress at the vents and has way lower pressures than ther Seltec system.

AC is really a black art

[BlackbirdM3]

Where is the sight glass in the system? Is it on top of the dryer? I have a hex head stop screw looking thing that is the only thing that looks like it could be the sight glass, but it was painted over from the factory from the looks of it.

I picked up a can of R12 and a set of R12 gauges with hoses for $45 this afternoon so I figured I'd give recharging the system a shot. Everything appears to be working, its just not cold. The air out of the vents is colder than the ambient temp but not by much, perhaps 10 degrees if I'm lucky. At this point all I need is the right can tap which should be here later this week.

Will

[jeffnhiscars]

Where is the sight glass in the system? Is it on top of the dryer? I have a hex head stop screw looking thing that is the only thing that looks like it could be the sight glass, but it was painted over from the factory from the looks of it.

I picked up a can of R12 and a set of R12 gauges with hoses for $45 this afternoon so I figured I'd give recharging the system a shot. Everything appears to be working, its just not cold. The air out of the vents is colder than the ambient temp but not by much, perhaps 10 degrees if I'm lucky. At this point all I need is the right can tap which should be here later this week.

Will

Assuming you have enough r12 in the system some other possibilities are a plugged expansion valve, weak compressor or air that has gotten in to the system which will make a recharge impossible without pulling a vac (and of course replacing the dryer). More r12 please.

This is my fresh Behr dryer and the sight glass is under the black rubber stopper that is dead centre on the dryer just to the right of the green HP switch. I didnt think I had one either til I realized that pried out.