When I did my conversion on my 2 GM vehicles, I did not notice any appreciable difference. They still got cool enough on really hot days, but yes it may take slightly longer. It was still well worth it to me. I would do it to my LC if it didn't already have 134.
AC is always going to be less effective at idle because the compressor is just not turning fast enough, one way to address this is to simply keep the RPMs above 1000 or so. R-12 and R-134a are so similar that its unlikely there will be any appreciable difference at idle (or any other situation). If you're looking for extra cooling people have installed electric fans to provide extra airflow to the condenser at low speeds.
I might be able to help you. I'm in Tucson and spent 10 years in the automotive A/C business. The compressors for the R12 systems and the later R134a systems are identical except the early compressors came with oil for R12 (ND6 or mineral oil) and the later compressors came with ND8 or PAG46 oil. You can use the later compressor, which are easy to get, if you want to stay with R12, just dump out the oil the compressor comes with and put mineral oil back in. Change the receiver/drier for sure. You only need to flush if there is debris from the old compressor, unusual in this application. You can find R12 on craigslist. I can supply the parts you need at a pretty reasonable price, as I work for Merle's. Let me know if you have more questions or need advise.
Rex
520-982-2533 cell
520-690-0922 work
If I'm interpreting this correctly they took 3 similar vehicles each running a different refrigerant and measured the pressures and vent temps? What jumps out to me is the R-134a low side pressure- 25 psi is likely undercharged. The website also claims that the low side R-12 pressure was "right on the money" at 28 psi. This isn't a valid way to compare refrigerants, the pressure varies with how much refrigerant is in the system and the ambient temp.
It looks like they compared 3 cars and the R-134a car was undercharged.
The compressors for the R12 systems and the later R134a systems are identical except the early compressors came with oil for R12 (ND6 or mineral oil) and the later compressors came with ND8 or PAG46 oil.
Interesting, my buddy and I were talking about it last night. We both noticed that we were running higher pressures than he shows. Thanks for pointing out that flaw in the data.
Keep in mind that the r-12 and r-134a driers are different...same size and shape but different ports on top. The 134a drier has much larger ports and will not bolt up directly to a 134a system. You will need more that just a drier and expansion valve to do a proper 134a conversion. Your r-12 drier isn't meant to work with PAG oil, not saying it can't, but it is not meant to. Freeze 12 as mentioned is/was a good alternative....if you can find any. Try buying an aftermarket clutch from the local auto parts place, if it doesn't fix the issue and your compressor is seized the you can return the part and know for sure you need a new compressor. My girlfriends dads best friend and family friend owns an AC shop and when I called asking for gaskets for a york I use for onboard air he said they don't do rebuild parts and gaskets because there is no money in it. I asked what about good compressors with bad clutches he said "same thing, no money in it" so chances are your compressor is decent and your clutch is garbage, or someone got tired of a squealing belt and removed it...I did until I replaced my idler pulley and separated and cleaned the rust from my compressor clutch pulley.
I would try to keep it R12 as it keeps things simpler. A new Denso compressor runs $268.99, the drier is $16.49 and the expansion valve (if needed) is $30.99. Three cans of R12 will set you back about $120-150 via craigslist. A bottle of mineral oil (A/C specific) is $5.00. I can get you a new clutch, but why take a chance and spend $170 on a clutch when you can get the compressor with clutch for <$100 more, and no shop I know of will take back a clutch once it's been installed.
well, I guess I stand corrected. I had read that R12 could only be bought legally with a license now... The Internet for you... It makes sense actually that they can't prevent people who had legally bought cans way back to sell them. Not that they won't try anything these days...
I have a 1991 A/C compressor that I converted to 134A worked just fine! I blew my motor and no longer need it.
Pay the ride, ill box it up and its yours! Its greasy but it works, 112F you need it!
I have a 1991 A/C compressor that I converted to 134A worked just fine! I blew my motor and no longer need it.
Pay the ride, ill box it up and its yours! Its greasy but it works, 112F you need it!
