finding AC Leak when the gas has gone

[derek griffiths]

Hi All, I haven't been her for some time but I still have my 97 Explorer in the UK and I try to keep on top of it. The job at the moment is sorting out the none working AC. The compressor wasn't coming on, so I shorted the low pressure switch and it activated fine. I therefore decided that there was a problem with the gas pressure, so I booked it into a garage for re-pressurisation. When they put the machine on the car, it went through its tests, including a pressure test, which the system failed.

This means there is a leak in the system. I have inspected as much of the system as possible but I can't see any sign of a leak. I then looked at adding leak detection dye but apparently I can't do this because the system is depressurised.

Does anyone have any advice on this? Is there a way to put a dye or a sealant in the system when it doesn't have pressure. If I kick the compressor in my shorting the low pressure switch, will that pump dye or sealant around the system? Finally are there any common places the Explorer AC leaks from, or should I just give up and accept the car no longer has AC.

I thank you for any assistance you may give....Derek

 

[XLTrunner]

I'm no A/C expert by any means, but I did just overhaul my system after a seized compressor due to loss of freon/PAG oil over time and lack of use. I added PAG 46 dye to the system when adding freon for future diagnosis (only takes and ounce or so) via the center hose on my gauge set that's used to add freon. Used an eye dropper and poured it into the hose before connecting to can of freon. I also saw where there were cans of freon with dye (considerably more expensive) and you can add that to the system. Have no experience with sealant additive. Of course, you'll need a black light with the dye to detect any signs of leakage. Common leak points are the schrader valves and compressor seals; although, I just replaced the condenser on my daughter's '10 Ford Edge w/115K miles that literally blew a pinhole...so, I guess it could leak most anywhere in the system.

 

[TsherryUSA]

As XLTrunner said, add dye when recharging. There are also recharge kits that include the dye, which makes it easier.

 

[C420sailor]

Piggybacking. Recharge with dye. Find leak. Vacuum system. Repair, recharge.

Other option is to simply recharge and use an electronic leak detector.

 

[Mbrooks420]

If it’s lost all pressure it’ll need an evacuation at the very least.