I recently had an issue that caused me to have my AC recharged. That charge lasted about 4 days before it was gone. I went back to have a leak test done and they could not find anything. They recharged and now 5 -6 days later, all gone. Any ideas where the leak could be? I replaced the o-ring on the low pressure line that goes into the dash behind the glove box. HELP!!!

 

I believe that they usually put a UV dye in with the refrigerant when doing a recharge these days which makes leak tracing easier. That's how I found my 'porous' condenser.
I'd recommend you get a LED UV torch: they're pretty cheap from the likes of Amazon:

I'd also change the dryer once you've tracked down the leak.

Out of curiosity, what is the cost of having the evac/recharge on your side of the pond?

 

They did add the dye and could NOT find anything. leak test was $35 and a full recharge was $199.

 

Odd: the dye/UV test is pretty sensitive and you must have a fairly substantial leak to lose all in a few days.
Only place I can think of in that case is somewhere that's not too accessible - perhaps the evaporator inside the car, but I guess they'd have thought of that?

Thanks for the info - I paid much the same. Seems expensive, although probably just me being a cheapskate.

Good luck,
Mike

 

I had trouble finding a rather large leak in my AC. After replacing all the o-rings where I could see any dye traces, I discovered that it was a relief valve on top of the drier. I found it from an audible hiss. There was no dye present.