I'm having a hard time getting a straight forward answer. But my ac system has all new parts except the compressor. I tried to recharge the system and evacuate it about 6 months ago but the compressor never kicked on. So I thought it was broken. Just recently I jumped this gray and yellow plug that isn't plugged into anything, but is coming off of the wire plugged into the accumulator, and the compressor will kick on and then squeal for a bit then shut off. Is that possibly because there isn't any refrigerant in the system to lube the bearings and clutch? Should I try to evacuate the system and recharge it again?

 

There is special lubricant for a 134a system that needs to be added. I'm assuming you read how to jump those wires from a thread the other day. All the info you need is there. It specifies quantity of oil and procedure for vacuuming and refilling the system.

 

Good info here > https://www.cherokeeforum.com/f2/air...-start-131879/

 

I have somewhat of the same problem, a loud squeal upon engaging the A/C, which disappears quickly.

In the above mentioned thread (this one was started so as to not jack that one, I think) it was said that either the belt is worn (1/4 turn test says it's not) or the compressor is about to go.

I am no expert (****, I'm not even a novice... just new and dumb) so answers aren't something I have, but it's about to get hot here and A/C would be cool (heh).

I have the benefit of excellent POs, older couple who took great care of the Jeep and who had it serviced at the same place pretty much it's whole life.

This leads me to believe, as someone mentioned in the other A/C thread, that my compressor fubar.

If anyone has any other answers to this, I'd be very interested in hearing them. I don't think the OP ever got a definitive answer to his question on vacuuming and recharging for this problem as it was different from the OP in the other thread.

 

I think I may go ahead and try to recharge it soon.

 

Did you pull a vacuum on the system after you got it all back together?

 

Yea I vacuumed it out, then went to fill it up with refrigerant and the compressor never kicked on. Maybe next time I should jump the compressor while I'm filling it up and it might stay running?

 

Anyone?

 

How are you vacuming it out?

 

Here is your straightforward answer:

Replace the compressor and clutch with brand new, not reman or used, parts.

Vacuum well and recharge. You should enjoy cold air for a long time.

 

With a ac vacuum pump and an ac manifold gauges set.

 

So you wouldn't even suggest, before replacing the compressor, trying to vacuum it out, recharge it and jump it while it's recharging? Because the compressor will kick on when jumped.

 

Yo Yo's next suggestion will be to replace the entire Jeep with a Yugo! Where do these guys come from?

If the compressor runs by jumpering the LO switch, put your gauges back on, at least the LO side.

static - engine off, it takes about 30 lbs pressure for the compressor to run. -- 1 12 oz can's not enough.

Jumper the connector, start engine, watch to LO pressure side - it will read very lo. Add till it reaches about 35 lbs, remove jumper, put connector back on the switch. It should continue to run fine, maybe still cycling a little.
put a temp gauge in the vent, windows closed, ac on HIGH RECIRCULATING. Notice the temp drops as you add more. At some point it will stop going down, STOP - IT'S FULL.
Also watch the Hi side - if it hits 200 lbs something is restricted - stop, find out why.

Depending on the environment, it will be lower than 40 degrees, should not go lower than about 30. Too cold ice forms on the outside of the evaporator coils, (not internally) lowering efficiency.

No need to vacuum it again unless you've had the system open.

let us know how it goes!

BTW """""Yea I vacuumed it out, then went to fill it up with refrigerant and the compressor never kicked on. Maybe next time I should jump the compressor while I'm filling it up and it might stay running? """""
You cannot get enough pressure in the system for the lo pressure switch to close and the compressor to run without jumpering the pressure switch.
a 12 oz can has about 12 lbs in it - not enough to start. The compressor has to run to "suck" it in.

 

Wow. That helped a lot. Thanks a bunch. So as soon as I start to fill it up, should I jump the switch? And if the compressor turns off should I just continue to jump it until it's full and stays running on its own?

 

"the compressor will kick on and then squeal for a bit then shut off. Is that possibly because there isn't any refrigerant in the system to lube the bearings and clutch? Should I try to evacuate the system and recharge it again?"

I am not an A/C certified tech, but I have spent thousands of dollars over the years having A/Cs worked on, on many vehicles.

The clutch is external; it is not lubed by refrigerant. Internally, the compressor is lubed by oil. The refrigerant is only a little oily on it's own.

The starting, squealing and shutoff is indicative of a nearly locked up or locked up compressor. You can vacuum, jumper, attempt to charge all you want. In the end, I still stand behind my earlier post that you will sooner or later likely end up replacing the last components you haven't replaced yet.