Imperial Homepage -> Repair -> Air Conditioning -> Leaks
Tips from Jack:
Given the price of R-12, the best way to test for leaks (at least initially) would be visually -- examine the A/C lines throughout for oil patches, especially at connections. The oil is A/C compressor oil that is carried out when the refrigerant escapes. Then, I would check by evacuating (assuming that some refrigerant remained in the system) and pulling a vacuum. Pull a vacuum for about 30 minutes. Then check to see that the system will hold that vacuum for at least 2 minutes. If the visual inspection/vacuum tests work and the system still leaks, you will need a die injection along with about a pound of R-12 to find the leak which will likely be very small.
Additions from Joe:
Here is another way to check for leaks if you do not have a sniffer. Mild dish soap, a cold engine and lightly soak each fitting, one at a time and look for visual bubbles and look for very tiny ones if no large leak is found. I have a sniffer and if there is any contaniments near the fitting, a false reading could be created. I do both, but the bubble system is a back up after my sniffer is used.
Question from Tony (1956):
I had my compressor rebuilt, and all under the hood checked for leaks. Checks good. However, the Freon doesn't last more than 45 days, then warm air is what I get. The air conditioner was not used by the previous owner (for 12 + years!), so I believe there are other check/replacement points that must be looked at in the trunk unit. Can anyone please help with what should be done to correct the situation? Should anything be replaced back there?
I am no mechanic!!! So please tell me specifically what should be done and/or where I can find the instructions/parts, etc.
Replies:
From Dick:
You need to take the car to an AC shop that has the right equipment to track down your leak. There are so many places the leak could be that it would be pure guesswork for me to advise you. A good leak detector should be able to spot that large a leak.
From Sherman:
On the 5 AC front (Tony), I bought today a complete test kit with glasses, dyes, light etc for a whopping $45- a good investment. Anytime you have remote units or components-there are lots of connections- these must be located first and then each checked for leaking. sometimes oil will leave a trace.
From Philippe:
I've also had the same problem on my '57: no visual leakage (there's a UV dye in the system) but after some weeks, warm air, rather, no cooling taking place!
I am going to try to add an "A/C stop leak". A friend of mine tried it on a car and it worked!! He put "A/C stop leak plus" from Uview (see http://www.uview.com/homepage.html) but there's a lot of other brands. It's not cheap, but I don't want to remove the evaporator cover.
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