When I purchased the car last summer the AC worked great. Previous owner said it had a new receiver-drier, and I found the receipt for it. He also said it was "upgraded", and I assumed that meant to 134A from the old R12. It has no new stickers indicating it now uses 134A, but the one accessable fitting on the low pressure line takes the 134A snap on connector (tho it has a RED cap). Can't find a 134A high pressure fitting. So much for history.

This spring the compressor didn't start, and I assumed the charged leaked out over the winter. It runs if I short the pressure switch with a paperclip, so that part is ok. I took it in to the school career center where I work part time, and before I could get to them, they hooked up the 134A connector from their AC charging/cleaning unit to the only fitting that would accept it, but it would not take any refrigerant. Running the car lowers the pressure in the line hooked to the canister, so I assume there is some vacuum. When it wouldn't accept refrigerant, I had them stop because I didn't want it mixing stuff if it hadn't been converted. My question is would there be a fitting on an R12 system that would accept the low pressure hookup for R135A?, and if so, could I have contaminated the system somehow? How can I determine if it has been converted. The previous owner is mostly duh. Thanks.

By the way....what I know about AC will fit on a pin head

Craigi38831.5736458333

The low side port, should be next to the low side pressure switch, on the evaporator. If the previous owner put a 134 port on the line it would most likley be 134. I would evacuate, find the leak, pull a vacuum and charge the system. 

[QUOTE=Kiltime]The low side port, should be next to the low side pressure switch, on the evaporator. If the previous owner put a 134 port on the line it would most likley be 134. I would evacuate, find the leak, pull a vacuum and charge the system. [/QUOTE]

Thanks. That is what I thought. Here are a bunch of pictures I just took. The fitting with the red cap is just above the pressure switch. Way down below is the "evaporator?, accumulator?, aluminum canister with a couple fittings on it. Other shots are just around the system. Does that sound, look like a converted system?  Thanks

edit::::  I just noticed my lines say 134A. I think that answers my concern about it being converted. I can't imagine them replacing all that stuff and dumping R12 back in

http://community.webshots.com/album/549797630AfrVaK

Craigi38831.6500115741

It's highly likely it has R134a in the system.  The fitting for R12 are different, and the products don't interchange without a lot of messing around that there is no reason for onyone to do.  No pro would do that.   If you evacuate the system completely, it doesn't matter.  All the old stuff will be gone, and the 134 can go in.

[QUOTE=kstyer]It's highly likely it has R134a in the system.  The fitting for R12 are different, and the products don't interchange without a lot of messing around that there is no reason for onyone to do.  No pro would do that.   If you evacuate the system completely, it doesn't matter.  All the old stuff will be gone, and the 134 can go in.[/QUOTE]

I feel lots better about it now that I really looked into it. What had me jolted for a minute was that red cap. It has an H on it (for High Pressure?), and 12 on it (for R12?). And it fit the fitting - kinda. They musta just stuck whatever was laying around on it to protect it. I'll take it in and find out why it won't accept refrigerant. I must be doing something wrong.

 

Thanks for all the help, guys. Wish I could make the trip south for the get-together. If I do go, it will be very last minute, if something else cancels. Probably have to sleep in the car

I have run into some 134 retro fittings that are not exactly correct. It's possible that the fitting on your car is messed up, and just won't allow refrigerant into the system. There is a small rubber "ball" down in there, and they can get stuck/swollen to where it just will not release. I'd say drain the system, and replace that fitting. Then go from there.

[QUOTE=Adams' Apple]I have run into some 134 retro fittings that are not exactly correct. It's possible that the fitting on your car is messed up, and just won't allow refrigerant into the system. There is a small rubber "ball" down in there, and they can get stuck/swollen to where it just will not release. I'd say drain the system, and replace that fitting. Then go from there.[/QUOTE]

Good Idea  It really acts odd, and I WAS able to get it to take some refrigerant earlier with a refill kit, but it was a tough time getting a seal - just like you described. It acts like something is stuck. I have a feeling the check-valve is shot. Since it's so low - or empty - I'll have that done. May be my slow leak, too!! Thanks Joel.

 Adam brings up a good point about the correct fitting. I would also check to see if they removed the schrader valve before they put the new valve on. It should be removed. I found out the hard way the system wouldn't take a charge. Removed it and reinstalled the 134 valve.

[QUOTE=Kiltime] Adam brings up a good point about the correct fitting. I would also check to see if they removed the schrader valve before they put the new valve on. It should be removed. I found out the hard way the system wouldn't take a charge. Removed it and reinstalled the 134 valve.[/QUOTE]

I checked and the low side fitting over the switch is 134 compatable and the schrader valve is free (I tapped it with a golf tee and got a quick psst).  I was able to hook up a can of 134A and let it sit for a while, and it took it (engine off). I then hooked up another can (system still low so compressor wouldn't start), and it took for a while then stopped. I started the comp. via the switch override, and pulled for a while until can 2 was gone. No comp. yet. and my low side pressure in the system showed about 35 pounds with engine off, and about 10 with the compressor running. Get cooling, but the compressor won't start. Might be that it was only about 50 degrees outside. I'll try again when it's warmer, and see if it works. Odd.

The system will need more than 10psi(running) to engage the comp. clutch. Most systems have the low pressure cut-off at around 20psi. Remember, too, that 134 runs at higher pressures/temps than R12. I'd say blow another can in it, and it should start to work.