R134a Conversion Questions

[KenMAthisHD]

I have a 1992 K1500 I’m wanting to convert to R134a, the system hasn’t been run in I want to say 2-3 years. From the research I’m doing, my understanding is that to convert the system properly you need to change the fittings to R134a fittings, vacuum any existing refrigerant from the system, flush the system thoroughly and replace the accumulator, gaskets, seals and orifice tube, drain the oil from the compressor, ensure there’s no oil in it and then put the PAG oil in it (I think like 4oz?), turn it a few times and then once everything is hooked back up, pull vacuum on the system for like 20 minutes to make sure you don’t have any leaks. Since I know it’s been filled with r134a before, but I don’t know if it had r12 when it was filled, I’m gonna be replacing the compressor anyways. I’m also going to be replacing the rad for an unrelated reason, so when I do that I figure I’ll replace the condenser too. I’m looking at a UAC compressor kit on rockauto, it’s almost $300 but comes with the compressor, new gaskets and seals, new orifice tube, new accumulator and a new condenser as well as PAG oil. Has anybody used this kit before or what have y’all done to convert to r134a in these systems recently? Is it better to convert to a 95 condenser, and what will I need to do that? If I convert to the 95 condenser, will I need to use an orifice tube from a 95, or will I need to use one for my 92 model year?

I’ve got a bit of understanding on how the system works but not a ton, and advice is appreciated.

~Ken

 

[man-a-fre]

I used the same kit from Rock auto on my 1993 k1500 works great been trouble free for 5yrs and the compressor is quiet.I went ahead and put a new condesor on at the same time to be sure it didnt have any debris from the old one,made flushing easier and was a real 134a condenser, my air is cold!

 

[KenMAthisHD]

What condenser did you use if you didn’t go with the condenser from the KT2362A kit? Would you happen to have the part #?

 

[man-a-fre]

I don't but it been a while,the kit i bought at the time didnt come with the condenser but was all uac .The condensor i ordered off ebay from a vendor in Texas.You'll probably be okay with the uac condenser.Just pull a vacuum as long as you can i let mine set 24hrs. and don't get in a hurry,and displace the oil in each part of the system compressor condenser,drier/evaporator.

 

[351FUN]

Did you get this conversion finished? If so, would you mind sharing the Rock Auto part number you used? My compressor is bad so I need a new one anyways and I want to convert while I'm at it.

 

[schwinnman67]

If you are going to do the conversion, get the parts for a 94... That is the only year with the old style dash that was R134 from the factory.
My friend did the conversion on his 89, we just changed the condenser and receiver dryer (94 parts). You do have to flush the lines and evaporator and use ester oil. If you were changing the evaporator also (along with the condenser, receiver and compressor) then you would use PAG.

 

[PlayingWithTBI]

You do have to flush the lines and evaporator and use ester oil.

134A & PAG oil are not compatible with Ester oil, you'll plug up the system. When doing the conversion flush the entire system then install new orifice, drier/accumulator, compressor, condenser, and add 8oz PAG oil, suck it down to -29" for at least 1 hour (overnight is better) and shut off the vacuum pump and see if it holds vacuum. If it does, then add the appropriate amount of 134A. If you don't eliminate the Ester oil, you'll fight it the rest of your life.

 

[schwinnman67]

Ester oil is the only oil compatible with R12 and R134.

Ester oil is a synthetic lubricant. Ester molecules are very stable and have excellent performance characteristics in both high and low temperature environments. Ester oil is typically used in systems that have been retrofitted to R134a, and it comes in only one viscosity so it does not contain the viscosity numbers associated with PAG oils. It is used in retrofit systems primarily because its chemical properties do not change when it comes into contact with the trace amounts of chlorofluorocarbons that are found in retrofitted R12 systems.

 

[PlayingWithTBI]

Ester oil is the only oil compatible with R12 and R134.

My bad, I don't know why I was thinking mineral oil when we were talking ester.

 

[blackdeathmessenger]

If you're replacing the compressor and condenser anyways, you should use Pag 150, which is what's recommended with the aftermarket parts for a conversion, since you mentioned flushing the system anyways. If you replace with aftermarket parts for your specific year (including orifice tube) everything should be fine