Project 97: A/C Maintenance & Upgrade

[Wayne 962]

Got any questions on Project 97 for your E36 or E30? Ask them here!

-Wayne

[dwillard]

Wayne,

The info in Project 97 on retrofitting an E30 from R12 to R134a alone is well worth the price of the book. By using my ETK software and BMW Repair Manual to cross-reference the numbers you gave in the article, I very quickly determined that my '84 318i A/C compressor will work with R134a --- big bucks relief on that!.

I do have a couple of questions, though. In the project you mention a BMW Tech Bulletin, "BMW Document #64 05 96".

Where can I get a copy of this document?

Also, you mention a kit needed to retrofit my compressor. I have checked the kits offered by Pelican Parts and did not find anything similar.

Is this a dealer-only item?

If not, who else might carry this kit?

Thanks.

Digby

[Bear]

First, I would put some flourescent dye in the system to ensure you have no leaks, if she is leak proof (here goes the heretical statement) try a drop in conversion, one of those Wal-Mart , $30.00 or so items. I did this on a 1990 325ic (build date of 05/89) six years ago and she still blows ice cold air. I did a full blown conversion on my '88 750 with new receiver/dryer, and expansion valve, vacuumed her down and the put in the 134a in to and in theory non-134a compatible compressor and that was over seven years ago and she still blows +40 degree "F" air in +95 degree "F" ambient temperatures.

[dwillard]

Bear,

Thanks much for your insight. As it happens, I have absolutely no experience with auto A/C except for turning it on/off and paying the bills to get it fixed when there is a problem.

So how do I get fluorescent dye into the system? I bought the car thru eBay a few months back and it was described as "A/C not working", leading me to suspect leaks as the problem. My sight unseen diagnosis was that the refrigerant had leaked out, although I do know this for a fact. A leak test, however, would give me some indication whether or not refrigerant loss is the problem.

Also tell me more about the "$30.00 Wal-Mart drop-in conversions". I'm clueless on this. What do I even look for if I do a search on the Wal-Mart website?

Sorry to come across as such an idiot. I'm a professional mechanical engineer and some people consider me to be a fairly talented machine designer --- but definitely not in auto A/C.

Just for info, the eBay listing for the car described it as having a "non-running motor because of low compression". I know enough about E30 318's to suspect that this was not in fact the case. I bought the car under these conditions, however, and was right---it runs quite well, thank you, after I took care of a few relatively minor issues. This leads me to suspect that the A/C problems were perhaps not diagnosed correctly, either.

Take care.

Digby

[Bear]

First the dye. most auto parts stores sell the dye in pressurized containers, you screw the threaded end of the container onto the low pressure refrigerant fitting (that is the thickest of the two refrigerant lines) and with the engine running and AC on the dye is sucked into the system. Then as the dye circulates it will push out past any leak points and with UV goggles and a black light the dye will glow a chartreuse color. Second the conversion, again sold at Wal Mart or any parts store, this is a kit with new fittings for the refrigerant ports, special oil (PAG or Ester) hoses to inject the refrigerant and probably about two cans of 134a. I suggest a Haynes manual for your car (the lest expensive, but the Bentley is the ultimate and all owners should have one of these). Go to a parts store and check out the kits and maybe talk to a part person familiar with the kit. I am not saying this is the only way to go, but I have used it (on the kids car) and it worked. Newere cans of 134a are even designed for older, higher mileage cars and have some sealeant in the refrigerant to help expand older dry seals and shore up the system.