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Air conditioning

xCWolf

Bring the Boom
NAXJA Member
Location
Boston
So my AC doesn't work (big surprise right?)



I have replaced -
Condenser
Compressor
Accumulator/drier
All Lines


I pull vacuum and it holds for hours.


I charge the system and its audibly leaking. LOUDLY


I pull vacuum again. fine.


I can't fathom what the issue is or HOW it's leaking.



Has anyone seen anything like this? This doesn't make any sense to me, like from a standpoint of basic physics this doesn't make sense. Anyone have a direction for this like, what should I look at. I don't know where to (re)start.


2000 XJ i6 aw4
 
Last edited:
So my AC doesn't work (big surprise right?)

I pull vacuum and it holds for hours.
I charge the system and its audibly leaking. LOUDLY

It can't be both?
 
evap core?? looks like you already replaced everything else lol




I forgot about that. I guess my dash is coming off.


But why would it hold vacuum for forever AND leak. If I vacuum it down and close the valves shut the vacuum off and it holds at 26 it shouldn't be leaking I would think
 
Id try to pin point the source of the leak by sound, Try a several foot long piece of hose, say garden water hose, put one end to ear, and move other end around to hear for pin point location of sound. use like a doctors stethoscope.

When is it leaking, once pressurized with refrigerant a.c. not running?, or when running? or both?
,
there can be instances of a torn or distorted oring that might hold well under vacuum, but leak under pressure, acting as a check valve. Or a fitting may leak when it gets cold. In vacuum testing, I have come across a few weird ones.
 
You have a bad O ring somewhere — pull vacum pulls air out of the system
When you charge the system you now have pressure pushing out

Bet its a bad O ring thats getting sucked into a sealing position while in vacuum but once you reverse the pressure and charge the sysytem your pushing the Oring out of that sealing position and it’s leaking

I’d check everything I can see before tearing into the dash
 
What Heavyopp said.

You may have to pressure test it with some leak detector. When I did mine a while back, i changed out all the o-rings. Had 2 seal leaks to chase down. I went through a lot of R12 then. :(
 
schrader valve? on a couple car's I worked on the schrader valve leaks just a little bit. Not as big like you said tho... The cap usually "fixes" the problem

Maybe try filling with air so you're not wasting r134a? just a thought
 
A can of coolant with leak detector dye and a UV flashlight is the easiest DIY way to find the leak. Clean around all the fittings and then add the dye. After running the A/C for a while, the dye will collect around a leak and glow when exposed to UV light. Check the schrader valves, often sources of leaks.
As mentioned before, it sounds like a bad o-ring, leaking under pressure.
 
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