Automotive Air Conditioning Information Forum

Hi,
I have a 2004 cobra mustang w/60k that developed an A/C leak. The pump clutch was toast, replaced it and bearing assembly. Pump is clean no sign of leak. I found the discharge hose leaking inside of a loom and had it repaired. Charged, leaked out in one day.

System would not hold a vacuum. Checked service valves, OK. Hit all connections with soapy water. After a long search I found oil/dye residue on shop floor from the condensate drain. No residue on the car, because the drain is above the exhaust and burns off. I pulled the dash (no fun) and replaced the evaporator and dryer. New o-rings, pag 46. The old evap had oil residue on it, as did the case, so it was leaking. The new Evap was pressurized, so I have to assume it doesn't leak. Now the system holds a vacuum, indicating that a leak was fixed. Charged and leaked out in one day, again.

The engine/engine bay is very clean. I have a lift and can inspect to bottom side easily. I do not have a nitrogen setup so used a partial can of 134 to pressurize and look for the leak. I cannot find any trace of oil/dye.

I'm out of ideas other than to pull off the three remaining pieces to inspect, liquid/suction hoses and condenser. Any help or guidance appreciated.

Thanks
Justin

At 21 years old, the car might have a leak at the compressor shaft seal, one of the lines might be corroded-through (check for oil and dye under any insulation that might be present), or one or more o-rings/gaskets/threaded joints might be leaking, which so far have gone unnoticed. Do you live in one of the Rust Belt states?

Hi John,
Thanks for feedback.
The pump shaft seal is not leaking, got a good look at it when replacing the clutch.
There is no rust or corrosion on the car. AZ, garage kept, 60k miles. Never driven in the rain, very clean.

Okay, no front seal leakage or corrosion.

Next on my list would be the condenser. It tends to take a beating from road debris given its vulnerable location behind the grille.

Thanks for the help. I pulled some panels off to get a better look at the condenser. Thought I found something but no.
The system holds the vapor pressure in, 90 psi.

IMO the best way to locate a leak is to partially charge with 1/2 can of refrigerant, and then use a leak sniffer. They have a wand on them and you can get the tip of the wand into tight spaces. The price of these sniffers has come down. It is hard to imagine that the integrity of the shaft seal can be determined by any other method.
As far as the evap, put the tip of the wand into the drain tube and/or in front of the evap grill

Double-check the shaft seal by placing a shower cap over the front of the compressor or taping a leak-free, well fitting plastic bag around the same location. Give it an hour or two, then slip the leak-detector probe underneath the shower cap or bag. If the detector sounds off, you'll know for sure that the front seal is leaking.