91, 945, AC fully converted to 134a already and has new low fitting. Question. What do I do to get this AC working correctly? I pulled the conversion kit's cap off the low pressure port (near the accumulator) just to see if it was really a 134a port and got a little fizzing and oozing from the port for about 1/2 a second. Is that normal?

Next, assuming that that is not a big deal, where do I go from here to get the AC working correctly. The guy I bought it from said that last summer he had his mechanic charge the system and it worked great for the summer. Right now the compressor is not running when I have the air on and the fan on high. Can someone talk me through this so I don't screw something up on this AC system unnecessarily? Please let me know if you need additional info.

 

Leaking at the fittings is not a good thing but neither is it uncommon. The center "needle" portion of the valve screws in and out of the actual aluminum housing/adapter. It is possible the valve is merely loose (tightens w/ a special tool) or it was defective from the get go. All these valves seem to be Chinese these days; failure is routine.

 

the AC compressor control goes from the dashboard controller (its +12V when the compressor should be on) to the low pressure switch on the dryer/reciever to the high pressure switch on the condensor (at the radiator) to the compressor itself. I believe this circuit is mostly green w/ a red stripe.

I'd start the car, switch it so you think the AC should be on, and use a volt meter with the black lead connected to a good ground, then probe both sides of that low pressure switch... if one side is +V and the other side is zero, odds are pretty good you don't have enough juice left in the system. you could jumper across this switch if thats the case, and see if the compressor starts and you get any cold air out, but dno't leave it like this without having the system leak tested and recharged.

 

Thanks guys. I'll try to get on that and see if I can get any info back for the discussion. Swift, if that fitting is bad and the needle can't be tightened, how difficult is it to replace just that part?

1. Assuming the compressor does work when jumped, could I then simply add r134a?
2. Should I run a vacuum on the system before adding r134a to test for a leak and remove moisture?
3. Should I have the system evacuated, then run a vacuum?
4. The label that states the conversion was done, includes a note to use only Volvo ester oil. Necessary?
5. I assume I should avoid R134a that has PAG oil already, is that correct?
6. If I don't evacuate and pull a vacuum, do I need to add any oil?

I definitely want to do this right- don't want to mess something up. I'm afraid that could happen since I don't know too much about AC systems. But I'm more than willing to try and learn.

Let me know.

 

I'd say 2. its the only way you know you are adding the right amount of R134A, but I'm not a qualified A/C technician.

assuming there is the right amount of oil in the system now, you do NOT want to add any more.

isn't 3. the same as 2. ? you have to evacuate any residual R134a before doing any such vacuum leak test.

 

Good point Pierce about #2 and #3. When you evacuate, does it also remove oil?