04 Liberty 3.7L - Need some advice on AC System

[jimbrown]

Need some advice from some of you guys familiar with AC, which is a pain in the ass, if I do say so myself.

Basics
-No Cold Air
-Compressor does not turn on
-It seems there's no pressure at all in the system

If I understand correctly, #2 is because of #3. i.e, if the low side pressure is low enough, the compressor won't turn on. I assume the pressure is atmosphere throughout the entire system.

I will admit I pretty much let it get out of hand. At one point, I could hear escaping gas after I turned the car off (refrigerant), and now it seems the system is empty.

I now have to worry about component(s) being damaged because of atmosphere/moisture contamination. I don't know how to pinpoint the leak because there is no r134a in the system. If there was some pressure, I could have introduced UV dye into the low side and possibly pinpoint the source.

Other than taking it to shop, not sure what else I can do. Could I try putting a vacuum on the system and then somehow determine the leak from there? Then, repair the leak and attempt to refill the system and see if it can run without replacing any parts?

Your thoughts or advice?

 

[Conundrum2006]

Sadly it's probably the evaporator , those usually require pulling the dash.

That is what I have to do for the commander.

You could try to pull a vacuum and check if it holds, if you're out of freon you've got contamination in the system.

If your real lucky maybe it's a bad pressure switch or a leaking line, condenser, dryer, in the engine bay. I've had compressors that leaked around the from seal.

It's tricky to get it right, you can pull a vacuum and recharge it but that's only a bandaid because it is still leaking somewhere.


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[uss2defiant]

if you know the system is empty, you can see whether it can hold a vacuum.

 

[jimbrown]

if you know the system is empty, you can see whether it can hold a vacuum.

True. That could possibly reveal the severity of the leak depending on how long it holds for.

What about determining the source of the leak? Would I need to refill the system with refrigerant and get it to a sufficient pressure so that the AC compressor turns on and introduce a UV dye? That might get costly especially considering system components might already be compromised and it might all be for not. Is there any feasible way in determining the source of the leak with just a vacuum and not having to put refrigerant in their to push out the dye?

 

[tommudd]

Really in the end best bet is to have a full service AC shop check it out. You could end up spending more time and money trying different things than what they would charge to give a good once over.
Just my nickles worth.

 

[Logan Savage]

I bought a KJ that had no pressure in the ac system . I added a can of refrigerant & could hear it leaking out of the condenser . I replaced the condenser & dryer & pulled a vacuum on the system & it held . I added the correct amount of refrigerant & now have a good working system . I did sacrifice the can of refrigerant to find the leak .

 

[jja]

Why don't you replace vacuum with high pressure? Your system is full of air anyways so some more won't change anything. That way you could add the UV paint or just listen where the hissing comes from.