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How to tell if AC is converted to R134 or not?

SonicCougar99

SonicCougar99

NAXJA Forum User
Location
Williams, AZ
I have a 1989 XJ Limited with the 4.0, and my AC doesn't blow cold anymore. I know that this year came with the old R12 stuff, but there's a sticker on the radiator cowling that says something about AC service, but the writing on it has all worn away and I can't see what it says. Is there a way of looking at the AC compressor or the lines and knowing if it's been converted or not? If it has, then all I need to do is go get a refill can and recharge it. If not, then obviously I need to go get it converted which is a bit more of an expense than just a plain can of R134a. Thanks.
 
look at the service fittings. If it looks like a bigger tire style threaded fitting most likely it has not been converted. If it has what looks like a shop air hose fitting on it it has definitely been converted.
 
also many reputable shops have A/C identifiers & may not even charge you to see what % of what you have in your system.
 
Ok cool, thanks guys. I live in a pretty small town so all the shops are a little bit of a drive, so I was curious if there was something I could just look at myself and be able to tell. Maybe next week if I'm in the bigger city I will see if a shop can help me out and tell me for sure.
 
Good call on this question SonicCougar99. I was just researching this myself. My A/C comp says R-12 on it but has the "quick connect" air type fittings on the back side of it. From what i gathered is what was said already.

R-12 system has a "schrader" style valve for both high and low side of system

R-123a has the quick connect style fittings on high and low.
 
Shorty said:
take the caps off your service ports and post a picture of them-- we'll tell you what you've got on it.
Click to expand...

I will do this tonight when I get home, got a 12 hour shift at my new job ahead of me. Thanks.
 

CaliXJ,

Whether or not the quick connects are installed on the schraeder valves is not a confirmation of whether or not a R-134a conversion has been installed. While working on vehicle A/C systems I have found that the quick connects were not installed several vehicles.
There is a way to check to see what refrigerant is installed....
With the engine cold connect a refrigerant test manifold to the system service valves and compare the system pressure to the outside air temperature in front of the condenser coil using the PT chart below. The temperature and pressure should be within 2-3 psi of the given temperature.

hp_r134.gif


 
Last edited:
Will those number still work if you have a system low on gas though? Also im failing to see what or how this chart tells me if I have r-12 or 134a. Just what a system pressure should be with OAT? Enlighten me please.
 
Last edited:
Except there's no practical way to discern a few psi difference on some fat needle on an analog gauge. And if he has a leak, the chart becomes useless.

Bottom line is, it doesn't matter. Refilling with R-12 is very expensive and warrants considering converting if not already done. This would require evacuation of the system.

If it has, the only way to ensure a full charge is by weight. This too would require an evacuation of whatever's left (if any).

That's after the leak is fixed, assuming this is low refrigerant problem.
 
Update with pictures. Been working 12+ hour shifts for over a week and today was the first day I could take a picture in daylight.
IMG_20120823_114904.jpg

IMG_20120823_114933.jpg


And the sticker that the writing is worn off of.
IMG_20120823_115007.jpg
 
Thats def different than mine! And my Comp has a R12 sticker on it.. But that one looks more like R12 lines
 
FWIW, i think there have been a handful of people who switched over to the R123a system without any retrofitting parts - they only did a very thorough evacuation.
 
bigalpha said:
FWIW, i think there have been a handful of people who switched over to the R123a system without any retrofitting parts - they only did a very thorough evacuation.
Click to expand...


R123 is for large tonnage chillers and not for automobiles.
There is R1234YF which is a NEW refrigerant that will be used in the automobiles starting with the 2013 model year.
The refrigerant presently being used in new vehicles since 1994 and of which vehicle owners are converting to is R134a.
For best results you should replace the accumulator/drier and flush the system of the old oil.
 
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