1998 TJ A/C holding vacuum but cool air dies soon after

[deeptread]

Hi,

Just gut checking. '98 TJ, A/C quit years ago and never bothered to diagnose. I hooked up the gauges, pulled a vacuum and left it over night. Everything was right where it should have been in the morning. Proceeded to fill the system, AC compressor engages, and get cool air. I'll go out a few hours later and no A/C, like I never did a thing to it. When the compressor switched on, didn't sound all that great and so my hunch is that I have some leak in the compressor.

Before I drop some cash on parts and my time, want to double check if this is reasonable assumption or if there are add'l tests I could perform. I did send dye through, but didn't see evidence of a leak anywhere using blacklight. While I have the patient open, should I replace anything else like accumulator and hoses?

TIA

 

[Abendage]

Did you hook the gauges back up to see if you lost pressure?

If you are going to replace the compressor, at a minimum replace the accumulator and liquid line with the orifice tube in it. Personally, I’d replace the condenser for what they cost and flush the rest of the lines and the evaporator as well.

 

[deeptread]

Yep, hooked up the gauges and pressure is gone.

 

[Abendage]

Yep, hooked up the gauges and pressure is gone.

I’d keep looking for the leak before I threw parts at it.

 

[JKP]

Interesting, I've never seen one that would hold vacuum for hrs that leaked when charged.

If you don't see evidence of a leak under the hood with the dye, most likely the evaporator, which means ripping the dash out.

If the compressor is leaking, there should be oil on it as well.

 

[deeptread]

Interesting, I've never seen one that would hold vacuum for hrs that leaked when charged.

If you don't see evidence of a leak under the hood with the dye, most likely the evaporator, which means ripping the dash out.

If the compressor is leaking, there should be oil on it as well.

Before I go ripping and buying I'm going to do another leak test.

 

[JKP]

Look at the high and low side schrader valves and be sure they are tight.

Also check around the high and low pressure switches.

 

[KennethS]

If you don't see evidence of a leak under the hood with the dye, most likely the evaporator, which means ripping the dash out.

Check the condenser in front of the radiator, too. Could have been hit by road debris or something.

I would recommend replacing as many o-rings as possible when you start replacing parts.

 

[deeptread]

My thinking was that the compressor would leak only when switched on, which could make it hard to detect. I'm borrowing a friends leak detector to see if there's trouble with the evap before going any further, and basically re-test everything.

 

[richallen]

I’m curious if you took the next step and found anything new?

 

[glowell222]

I had the same issue, though mine would last about 3 days. I found a small leak on the condenser and the main culprit was the liquid line. I replaced the condenser and LL and problem solved.

 

[deeptread]

I’m curious if you took the next step and found anything new?

Yes I found the leak at the rear of the compressor. Which makes sense as the system held vacuum and would lose pressure over time as I used the ac. I bought a compressor off rock auto and will replace this weekend.

 

[KennethS]

Appreciate the reply. My new to me 2001 needs some AC love. I shot some 134 in and the compressor started operating, so I’m considering evacuating the whole system and charging from scratch to see how it runs. Thoughts?

Not sure why you would do that as opposed to charging it to the correct pressures and seeing what happens over time.

 

[deeptread]

Appreciate the reply. My new to me 2001 needs some AC love. I shot some 134 in and the compressor started operating, so I’m considering evacuating the whole system and charging from scratch to see how it runs. Thoughts?

There's a lot of things that could be wrong. Since you're under pressured, I'd send UV dye through and try to spot a leak, or use a leak detector. Then go to a full evac and recharge.

 

[deeptread]

New compressor arrived today. Installed, replaced belt while I was I in there, held vacuum for 2 hours, refilled-- Finally I have cold AC.

 

[KennethS]

That’s one heck of a hood prop.

 

[deeptread]

That’s one heck of a hood prop.

thanks, make it myself