A/C How to Tell What Refrigerant is Used

[indycar56]

I recently purchased 02102 that had been rebuilt by the previous owner. The AC is cycling on and off rapidly, so I assume it is low on refrigerant. How can I tell if the system is still R12 or if it has been upgraded to R134?
I don't want to top it up with the wrong type.

[Cartman]

I don't blive there is any way to chec other then to de gass it, and test the gas itselfe... chanses are if it's been restored that it's r134a, but I would recomend degasing it entierly, and the regassing it whit r134a. just to be shure :)

[Dangermouse]

You could possibly tell by the type of compressor installed. If it is OEM then it is most likely R-12

[Mark D]

I would think the easiest way would be to check the fittings on the compressor. If the refrigerant has been changed from R12 to r134a you'll have different fittings that allow you to connect to
r134a equipment. Otherwise if your compressor still retains its stock fittings then it would still contain R12.

I don't have any good pictures comparing the two, but the old R12 fittings on the back of the compressor usually have small brass caps and the newer r134a fittings have larger ports and colored plastic caps.

If you post a photo of your compressor we could identify if the fittings have been changed or not. When auto makers started using the newer refrigerant the fitting type was changed on purpose to help prevent people from filling their system with the wrong refrigerant.

If you are still running R12 you can find it on ebay or there may still be local shops that can install it for you. I had my car recharged with R12 at DMCMW. Otherwise if you decide to convert over to 134a you need to completely evacuate the system using the right equipment and make sure all the old oil is removed from the compressor. There are a few other threads here that describe the process in greater detail.

[indycar56]

I would think the easiest way would be to check the fittings on the compressor. If the refrigerant has been changed from R12 to r134a you'll have different fittings that allow you to connect to
r134a equipment. Otherwise if your compressor still retains its stock fittings then it would still contain R12.

I don't have any good pictures comparing the two, but the old R12 fittings on the back of the compressor usually have small brass caps and the newer r134a fittings have larger ports and colored plastic caps.

If you post a photo of your compressor we could identify if the fittings have been changed or not. When auto makers started using the newer refrigerant the fitting type was changed on purpose to help prevent people from filling their system with the wrong refrigerant.

If you are still running R12 you can find it on ebay or there may still be local shops that can install it for you. I had my car recharged with R12 at DMCMW. Otherwise if you decide to convert over to 134a you need to completely evacuate the system using the right equipment and make sure all the old oil is removed from the compressor. There are a few other threads here that describe the process in greater detail.

Thanks...very helpful. Attached is a picture. The compressor has been replaced and looks like it has the plastic fitting covers, so looks like r134?

[DavidProehl]

Thanks...very helpful. Attached is a picture. The compressor has been replaced and looks like it has the plastic fitting covers, so looks like r134?

Yes, that looks like r134

[Rich_NYS]

Thanks...very helpful. Attached is a picture. The compressor has been replaced and looks like it has the plastic fitting covers, so looks like r134?

From what I've read, that looks like 134a.



Surest way to tell if your car is converted to R-134a is if it has colored service port caps (blue and red) as opposed to the stock/OEM brass service port caps, or if there's an R-134 service port adapters on top of the stock R-12 service ports.

[TTait]

An R12 fitting has screw on threads, and looks similar to a tire stem with a shrader valve in the middle - a 134 fitting has a quick release type fitting similar to what is used on an air compressor quick disconnect - no threads.

It is possible to get 134 into the system without updating the caps - but you have to frankenstein together the service hoses to do so - and its poor form, so you have to factor in if the PO did really questionable work when thinking that way.

You might add some leak detector to the system- its a UV dye - then you run the system for a while and use a blacklight to look for leaks - it is available for either style fittings. R12 in particular is getting expensive - so if you have a leak it will pay off to get it fixed before putting hundreds of dollars of gas out a hole (and into the ozone).

Ten years ago some shops that do AC work would have had a gas analyzer that would detect what type of gas was in the system, but with R12 on the sharp decline I think you will find it harder to find one today - look for an AC shop that has been doing quality work for many years on many types of cars and they might have one.

134 and R12 can use different compressor oils, so if you are unsure and choose to de-gas it might be wise to flush the system as well with a proper refrigerant flushing product. Then you would add new oil, then new gas and start over.

Lots of different thoughts there - not a clear direction - but something might help.

Be cool! (pun intended)

T

[Mark D]

Yeah that looks like R134a to me too. Nice Island turbo setup you've got there also :cool1:

You should be able to go to your favorite parts store, autozone, advance auto, etc. and get a can of refrigerant with the right quick connect fitting. Most of these self recharge cans have a gauge on them and you just squeeze the trigger until the pressure reads in the green range.

If you're low on refrigerant there is a leak somewhere so the environmentally friendly thing to do would be to find the source of the leak and fix it... Otherwise it's not that uncommon for people to just top off their system every couple years if the leak is small.

I'm still running R12 and every 2-3 years I need to add a can. :shhh:

[indycar56]

Yeah that looks like R134a to me too. Nice Island turbo setup you've got there also :cool1:

You should be able to go to your favorite parts store, autozone, advance auto, etc. and get a can of refrigerant with the right quick connect fitting. Most of these self recharge cans have a gauge on them and you just squeeze the trigger until the pressure reads in the green range.

If you're low on refrigerant there is a leak somewhere so the environmentally friendly thing to do would be to find the source of the leak and fix it... Otherwise it's not that uncommon for people to just top off their system every couple years if the leak is small.

I'm still running R12 and every 2-3 years I need to add a can. :shhh:

Thanks to all for the comments. I am going to try a recharge tonight. One last question, does the recharge hose go on the blue covered connector? (low pressure)

[Mark D]

Yeah you'll want to use the low side port (blue) to recharge. The fittings should be different between high/low so the hose on your recharge can should only fit on the low side.

Have fun! :wrenchin:

[David T]

I recently purchased 02102 that had been rebuilt by the previous owner. The AC is cycling on and off rapidly, so I assume it is low on refrigerant. How can I tell if the system is still R12 or if it has been upgraded to R134?
I don't want to top it up with the wrong type.

The A/C compressor on a Delorean is supposed to cycle on and off. How rapidly is dependent on a few variables including:
Ambient temperature
Amount of refrigerant
Setting of low pressure switch
Speed of fan in cabin

The system could have been converted even though the service fittings have not. Look for a sticker indicating any changes. The only way to know for sure is to have the refrigerant tested. You can guess at it by seeing what pressures the system is running at.

[Ron]

Probably easier if you were in a hotter climate, but if you have access to a heated area, at 90F+ you could use pressure v/s temp to get a good idea...
http://dmctalk.org/showthread.php?1244-Refrigerant-Temp-Pressure-Chart

(I guess you would still have to assume it was not mixed and compatible with the oil...)

[Bitsyncmaster]

I would have to say if the R134a fitting are on the compressor than you don't have R12. But you now don't know who or how the conversion was done. Lots of conversions have been done by just adding a few cans of R134a after the user changed the fittings.

I think the static pressure is a little different between the two refrigerants but you would need a pretty accurate pressure gauge and have the car sitting at a constant temp for many hours.

Edit...you beet me to it Ron

[rileydawgg]

Since it's a new car and you don't know the history of the AC, it might be worth taking to a shop and have a leak test done first. You don't want to put in new refrigerant if you have leaks. These cars can get pretty warm... so for me after I bought mine, it was worth the $100 to have a shop do a leak test, and refill with the correct refrigerant for the peace of mind.