Hey there. I don't know if I'm just cursed with service on my Bonny, but now I just had a shop put in the R134A instead of using the R12. He just used an adapter & pumped it in along with some stop-leak.

Is this basically alright to do, or is it a big no-no like I've read? He says he'* done it with many of the older cars in the past.

I too have heard you need to modify your system before you can run the newer refrigerant, but I can't for the life of me remember why.

From what I've read now, the main reason is that the mineral oil with the old R12 system is not compatiable with the new R134a, & that the only real things that need to be done are to completely flush out the system & evacuate the old R12, & install the new type oil.

I'm trying to find out if that was even done. Now the compressor doesn't seem to be working right. Sporadic compressor on/off, but it'* pretty cool weather right now.

Right. Needs to be flushed out completely. How cool is cool weather? It should turn on even if its 50 degrees out.

Yeah, I just got ahold of the mechanic & he says he did flush out everything & put in the ester oil, at least. It was about 65F yesterday when it wasn't clicking on though. Was working today sporadically at 71F so hope it straightens out eventually.


Found on epa,gov:

"Least-Cost Aftermarket Retrofit

Many car owners may express interest in receiving a least-cost retrofit. Procedures required for a least-cost retrofit are simple and do not require major component changes. Generally, the process calls for removal of the old refrigerant, installation of new fittings and a new label, and the addition of either a polyalkylene glycol (PAG) or polyol ester (POE or ester) lubricant as well as the R-134a refrigerant. For many vehicles, this simple, least-cost retrofit should provide the vehicle owner either with a/c performance comparable to the R-12 system performance or with a/c performance that, although slightly reduced, is still sufficient to satisfy the customer. A least-cost retrofit, however, may not provide a satisfactory solution for certain vehicles."

If its turning off sporadically, check if the compressor is engaged during those times. Check the compressor clutch relay to make sure the leads aren't corroded, and check the pressure in the system while its running.

Will do - thanks much!

You can't mix R12 and R134a the oils aren't compatible and will break each other down and most likely will run a different pressures. It'* the same with with your home A/C and R22 vs. R410a.

At the VERY LEAST your entire system should've been evacuated, flushed and vac'd down before refilling with R134a. I would keep your receipt from that guy in case your compressor is shot

I suspect this swap was done on my car before I got it, and I notice that it does take a little bit to get cool, but does the job.

I guess I misunderstood him the 1st time. When I called him back he said he had done all that you list & put in ester oil.

What I'm wondering about now is that he evacuated 1.5 lbs. of R12, & it shows he put in 1.7 lbs of R134a. Wouldn't that imply that the previous R12 level was OK & it was/is something else wrong with the compressor? What'* the total refrigerant capacity?