A/C Woes

[luvin my 325es]

I got my reciever/dryer on ebay, paid $25 including shipping.
No sight glass, was only difference.
Never seen a pump like that, almost too good to be true.
I would look for 134a compressor.
Get a hose clean the condenser.

[Digitalwave]

The HR one is $10! It doesn't have gauges though.

[Digitalwave]

So far what I have in my shopping cart is:

expansion valve ($13)
receiver/drier (the $15 one, not the $63 one. I can't tell the difference)
R134a retrofit kit ($33)

Total is $71 shipped. Then add whatever it costs to get some cans of R134a, and the cost of having the system evacuated (hopefully I can just buy the Harbor Freight pump, it'd save me some hassle).

If I am opening up the A/C system to replace those parts, I will just remove the compressor and drain out the oil (I take it you can just pour it out?) and replace it with PAG oil.

[Koony]

Those gauges are showing you if the system is holding a vacuum. I'm telling you though, if you get that pump and manifold gauges you may not need anything else to get your AC up and running again. Well, besides r12 or a substitute such as http://www.freeze12.com/ and oil.

[Digitalwave]

I gotcha. Thanks for the link.

[325iCabrio]

Alright, so if I got one of those R-134a conversion kits from BMA that has all the new seals, got a new drier, and then evac'd the system I'd probably be good. What sucks is I don't even know if the compressor is good or not.

BMA lists 2 different receiver/driers. One is $15, the other is $63. Why the price difference, and which do I need?

Just different companies who make them. I double checked on Pelican Parts, and they list the two different receiver/driers too. I'd just go with the cheaper one; it's still made by Behr, which is an OEM part manufacturer.

I'd think with the conversion kit with new seals, a new drier, and a recharge of R134 would give you a pretty good system. It won't be as cold as R12, but it'll be better than nothing, especially in Florida! I used to live there, and I don't know how you got through five summers without AC in your car.

[benjlv]

from what I remember when i wanted to convert an old buick of mine is the following. PAG oil is what is used in new OEM systems with R-134a. Typically when you retrofit you use some other oil that has a E in the name as i recall. Anyways I forget why they use the other oil.

Problem with using R-134a in a R-12 system is the fact that the mineral oil in a R-12 system doesnt disolve in R-134a. So it doesnt get carried properly throughout the system. So a lot of these retrofit kits have a small amount of this other oil that you add to the system to take over lubrication duties in the system. I imagine that the old mineral oil still helps out. Anyways people out in the air conditioning forums tend not to think very high of these systems. Some people have success and others do not. I think it helps if the compressors is at a low point in the system. It seems that the oil would have a harder time leaving the compressor and easier time returning in such a configuration.

There are also other refrigerents like freeze 12 that have another gas in them to carry the mineral oil. Dont know what the success with these has been. Could be a good alternative.

Ideally you would flush all the old mineral oil out...switch to a R-134a compatable compressor and the proper R-134a oil (dont know if youd use the PAG or the E stuff). I have heard of cars having adjustable expansion valves so maybe there could be a performance benefit there if the e30 one is adjustable or if there is a aftermarket one.

Best thing to do is see what other people have been successful with in an E30.

Anyways these are a few random thoughts. I really just wanted to point you to this forum since back in the day I found some of the guys on there very helpful. Keep in mind many of them are shop techs.

http://acsource.net/acforum/

[Erick]

Thanks Stu.

I forgot to mention, my car is a 1990 so from what I read the compressor should already be R-134 compatible.

My black '90 was converted to R-134 so you should be good.

[Digitalwave]

Thanks for the post benjlv. What I am going to do on my system is replace the receiver/drier, expansion valve, and all the o-rings with an R-134a conversion kit from BMA Parts. Then I am going to drain the old oil out of the A/C compressor and replace it with PAG or Ester oil (not sure which yet). I'll then vacuum the system and charge it with R-134a. I'll report back when its done.

[Kruzen]

Thanks for the post benjlv. What I am going to do on my system is replace the receiver/drier, expansion valve, and all the o-rings with an R-134a conversion kit from BMA Parts. Then I am going to drain the old oil out of the A/C compressor and replace it with PAG or Ester oil (not sure which yet). I'll then vacuum the system and charge it with R-134a. I'll report back when its done.

Hate to bump old threads, but how did this work out for you?

[Digitalwave]

It worked fine. The a/c blew cold. If the car sat in the sun all day and I had to commute back from work in the afternoon heat and traffic it wasn't exactly freezing but after a bit the cabin cooled down, especially after I got out of traffic. At night and when the car is moving (not stop and go traffic) it was downright cold!