AC recharge

[mackguy]

Over the winter my HVAC started giving me the code for low refrigerant.

It?s getting warm here now so I?m starting to look at this. When I take the cap off the low side port it sprays at me, so likely a bad/loose valve to figure out first.

My car has a sticker saying it was converted to R134 and has the 134 style fittings.

I have 2 basic questions:

1) how much 134 does it take? I?m not sure if it?s 1:1 with R12?

2) do I need to do something (disconnect battery?) to reset the code before trying to charge the system or will it clear and start the compressor automatically once there?s pressure? I think the FSM didn?t mention anything about this but I don?t have it in front of me right now?

[mackguy]

Well I think I've mostly answered my own questions.

FSM says 16oz of R12, and online search says R134=R12*.9-.25lb, so .65lb or 10.4oz..

And I see there is something about bypassing the safety circuit on the auto climate control, I'll dig into that in a bit.

[secondchance]

When my 94 was low on charge, I hooked up AC Pro canister and charged until I got around 4.2 psi on the low side since I wanted to avoid over charging. Going by weight involves total evacuation and going to a shop which I wanted to avoid.
Also restored foam insulation on the high pressure line which pretty much disintegrated over the years.
Both high side and low side plastic caps were replaced with Dorman brass fittings since it was low side schrader valve leakage was the culprit.
BTW - low and high pressure psi are ambient temp dependent.

[mackguy]

Yeah, I'd like to just do that, but since it seems to have a valve leak, I'm guessing it's going to lose its charge when I fix that, and require a full recharge.

OReilly's appears to have everything needed to take care of it, just trying to make sure I've got everything in order.

Originally Posted by secondchance

When my 94 was low on charge, I hooked up AC Pro canister and charged until I got around 4.2 psi on the low side since I wanted to avoid over charging. Going by weight involves total evacuation and going to a shop which I wanted to avoid.
Also restored foam insulation on the high pressure line which pretty much disintegrated over the years.
Both high side and low side plastic caps were replaced with Dorman brass fittings since it was low side schrader valve leakage was the culprit.
BTW - low and high pressure psi are ambient temp dependent.

[secondchance]

https://www.amazon.com/Ausfyyam-Remo...%2C110&sr=8-11

Tool like this will allow valve removal/replacement without emptying the system.

[mackguy]

Yes, problem with those is there's no room to get it on the low side port. Not sure about other years but on 93 the low port is on the drier, facing the engine...
I got some 90 degree R134 conversion fittings to see if that will make access easier in the future.

Originally Posted by secondchance

https://www.amazon.com/Ausfyyam-Remo...%2C110&sr=8-11

Tool like this will allow valve removal/replacement without emptying the system.

[secondchance]

I was not aware of 93 having low pressure side port being on the drier. 94 shrader valve is on the passender side parallel to the motor.