Cool/Heat: How to find A/C leak?

[garyash]

For my 1965 Wagonaire, I put in a new Sanden A/C compressor, new condenser and drier, and new Mark IV evaporator/controller from Vintage Air. I made up the lines using A/C hose and used a compression tool to install the ends. I've pumped out the system and pressurized it with argon using a tank from my welder to save the cost of refrigerant. Unfortunately, the pressure leaks down over a day or so, so there must be a leak. I assume it is incomplete compression on one or more of the fittings.

So, how do I find out where it is leaking? I've painted on soapy water where I can reach, but I can't see behind the evaporator and the condenser fittings are also hard to see. I ought to pull out all of the lines, re-squeeze the fittings, and try it again. But, that means leaving the drier open for longer than I like. I guess I could just buy a new drier when I put it back together. It was a real pain to put the lines in place so I'm not looking forward to pulling them out and putting them back.

So, is there a simple way to check each line? My industrial experience says to plug the line ends, somehow pressurize them, and immerse them in a tub of water and a little dish detergent, then look for bubbles. I do have an electronic sniffer for halogen gases but haven't found the leak that way when pressurizing with refrigerant. Maybe that would work with the lines out of the car.

Summer is coming and I want A/C!

[yeroldad]

I'm guessing you could get a Argon sniffer, and I'd guess it wouldn't be cheap.

[Bo Markham]

Dye and a black light, perhaps??

Bo

[StudeRich]

Are you penciling out the Condensor, Evaporator and Compressor just because they are New ?
Could be a mistake.

[gordr]

If it's leaking down in a day or two, it has a major leak. I think there are ultrasonic leak detectors out there that can hear the sound of gas escaping. Maybe you could buy or rent one. Another thought: pressurize the system with propane, and use a combusitible gas sniffer, which are cheap and plentiful, to find the leak. Purge with argon after finding and fixing the leak.

[Captain Billy]

PAG oil available everywhere.....choose the correct for your application

Example:

https://www.amazon.com/dp/B008PKWD3O/ref=vp_d_fuw_pd?_encoding=UTF8&pf_rd_p=ae349ce4-92a8-48ca-859f-d5ce1043c4bf&pf_rd_r=AT1E4F6NVG90ZFJ7SR05&pd_rd_wg=JBVmw&pd_rd_i=B008PKWD3O&pd_rd_w=kg2rh&content-id=amzn1.sym.ae349ce4-92a8-48ca-859f-d5ce1043c4bf&pd_rd_r=cc241259-6367-4f32-8812-884ea8f09f92&psc=1

[jts359]

Years ago my brother got a New leaky evaporator from vintage air . Ed

[IndStudenut]

I agree with Bo ....... When I bought my 99 GMC the air was loosing charge..... I looked and looked and looked trying to find the leak. No luck... finally I put dye in the system waited until night for total dark and used a black light. Turned out the front seal in the compressor was leaking clear up under the bottom out of site. Of course that means you will be kinda wasting the 134a to find the leak. But it has been my experience that finding a leak is like finding a needle in a hay stack. The dye with out a doubt pinpoints the source of the leak. Dye is cheep and you can get a black light bulb cheap as well to go into a drop light.

My 2 cents

[Hawklover]

Another R-12 story: back in 2018 I put in a new (not re-built) compressor in my Avanti, with this went one new hose, and a rebuilt rec/dryer from Jon Myer. Well after all was installed it was found that the R-12 leaked out in about one month. To make a very long story short, the leak was found to be coming from the end of one of the hoses, no amount of tightening cured the leak..............then the shop owner remembered he had used special sealing washers years back that went into the hose ends when leaks were found to be from hose ends, they were copper as I remember. After the system was pumped down yet again and those special sealing washers were installed, no more leak!!...now as of 2025 the car still has no leaks. I would suggest you checking for leaks at the hose ends, and if they are, look into those sealing washers.