AC help, convert from R12 to R134
 

I bought the conversion connnectors for my W201 and and while I have little info on AC systems, I watched a good how too vid. I am going to vac out whatever is left in the system, it is holding some pressure, and then put it on a vac and see if it holds. If it does, going to reintroduce 134. Any reason why the old compressor can or cannot operate on the new juice?

Likely your system is still filled with mineral oil. It is not compatable with r134. It will run, but only briefly.

R134 can't carry the mineral oil and thus will run as if there is little or no oil.

Why don't you just buy a couple of cans of r12 on eBay and be done with it?

I have done a few R12-R134 conversions successfully and here is my experience. I do not normally flush the system as I am a shade tree A/C guy. The results may vary so it is your call. The steps I take:

1) Make sure the existing A/C works, I mean the compressor will come on when you call for A/C. You may have to jumper the low pressure switch at the receiver dryer to simulate a charged system, run it for < 30 secs.
2) I ALWAYS replace the rec/dryer when I do the conversion.
3) Pull vacuum and make sure it holds for a few hour, if not fix the leak.
4) Put 8oz of ester oil in system. ester oil will mix well with whatever was in there.
5) Replace or screw on new valve to convert to R134 fitting.
6) Charge with R134, A/C on and fan at full speed.
7) I do not measure pressure as such even though I have the manifold gauge.

Always wear safety glasses. Good luck.

OK, this sounds like a good plan. I have been meaning to buy a manifold but when I ask how I collect the old R12, they say just let it out. :confused: Man maybe way back awhen but I want to do my part. On the R12, how much do I need? 1-2#??? Is that oiled or do I need to add some esther/mineral oil as well? The system does hold pressure. How much I dont know. I will jumper the switch and at least confirm the compressor will engage.

I am fixing it up for a girlfriends kid, I live in San Diego too, and to me, its not super critical. Funny what people expect for a $2500 car.

Thank you guys.