A/C problems on 1999 Wrangler

[99black]

My 1999 wrangler will not keep Freon it leaks off.
It will hold vacuum without leaking off. I put 150lbs pressure on the system and it will not leak off but you pull vacuum on system and charge the air will get cold about 40F but by next day all of the Freon is gone.

 

[Only TJ's]

Did you check the O-Rings? If I recall from @NashvilleTJ's build thread, he had a similar issue and couldn't find it until he injected dye

 

[99black]

I checked and replaced O-rings

 

[TJ4Jim]

I checked and replaced O-rings

Similar problem a while back and could not locate a leak with the dye either. Purchased the HF sniffer and found an internal leak inside the lp switch that did not show dye, rpita.

 

[99black]

Dye is how I found bad O-rings.
Maybe I need to try dye again.
but it’s strange that it will hold vacuum and hold the 150lbs pressure I put on it.
Thanks! I will keep trying to get it.

 

[TJ4Jim]

Dye is how I found bad O-rings.
Maybe I need to try dye again.
but it’s strange that it will hold vacuum and hold the 150lbs pressure I put on it.
Thanks! I will keep trying to get it.

Being trained in A/C tech I found it strange the switch held over 2 hours in vacuum, never pressure tested the system as I did not have nitrogen handy.

 

[RobertJ]

I'm just thinking out loud here, but would it hold vacuum if it had a bad Schrader valve on the port you were pulling the vacuum from?

 

[CharlesHS]

I'm just thinking out loud here, but would it hold vacuum if it had a bad Schrader valve on the port you were pulling the vacuum from?

YES it would.... but seems strange that you wouldn't see the leak with dye injected....
IF you haven't already done a bubble test on the schraeder valves, the LP and HP cutout switches; then you should.

 

[mrblaine]

My 1999 wrangler will not keep Freon it leaks off.
It will hold vacuum without leaking off. I put 150lbs pressure on the system and it will not leak off but you pull vacuum on system and charge the air will get cold about 40F but by next day all of the Freon is gone.

Not sure how to find it exactly but we just went through this with one. Held vacuum, held on initial and first couple cooling cycles, seemed good. Next day, fully leaked down to non cooling again. Shop did dye the first time and each of the 3 times thereafter all with the same result. Not sure how they found it but finally it turned out to be a loose hardline that connected to the evaporator inside the HVAC box. The hardline couplers that the AC hoses shove into are in fittings brazed into the evaporator coil header and sealed with o-rings.

I'm actually not sure that it died on its own, after looking at the removed part, I think the AC tech pulled on it too hard trying to replace a "bad" AC line and that loosened it which later let it puke out the o-ring.

All I actually know is replacing the evaporator after several tries of getting the system to hold pressure and vacuum finally seems to have fixed it. They always replace the service port shrader valves, they said a pressure switch had a very slow leak and replaced it and they said it had a bad AC line. All but the evaporator work were credited back after they replaced it.

 

[99black]

Haven’t had time to do more checking but will be checking valves and going to try sniffer on it to see if it shows something.

 

[99black]

Finely found leak in ac. Leaking from compressor only when running.
That’s why it would hold vacuum and pressure when not running.
And the leak didn’t show up on front of compressor so you could see it but sniffer finally pick up on leak.

 

[Chris]

Finely found leak in ac. Leaking from compressor only when running.
That’s why it would hold vacuum and pressure when not running.
And the leak didn’t show up on front of compressor so you could see it but sniffer finally pick up on leak.

Glad you figured it out and thanks for the update!

 

[CharlesHS]

Finely found leak in ac. Leaking from compressor only when running.
That’s why it would hold vacuum and pressure when not running.
And the leak didn’t show up on front of compressor so you could see it but sniffer finally pick up on leak.

Thanks for the update on finding the problem.