AC leak detection

[William F.]

What's best method to detect source of an R12 leak? Chevy service manual says avoid introducing "dye" into system , says can clog, but many technicians use it. Please let me know your opinion and experiences with using dye or other method of leak detection.
Thanks

[Al R.]

Re: AC leak detection

William, I used the dye available at Autozone approx. 3 years ago and have not had any issues that I'm aware of. But it's also a limited use vehicle, so I don't know if that is a positive or negative. The AC does get turned on and run every 2-3 weeks to keep things in order. Run time is approx. 5-10 minutes each time. I would think finding someone with a GOOD electronic leak detector is best if you are currently chasing a leak, as that can pinpoint the leak and also lets you know if it is inside the box where dye would not be visible to the eyes.

[Jimmy G.]

Re: AC leak detection

There is a "SNIFFER' for Freon

[Larry M.]

Re: AC leak detection

I use an Inficon TEK-MATE refrigerant leak detector. This model is reasonably priced, and has a proven history and track record in the field for finding refrigerant leaks.

Leak checking with SNOOP (or its equivalent) is another way, but it cannot find all leaks. The TEK-MATE can.

Larry

[Mark E.]

Re: AC leak detection

William,

The CSM describes the 50 year-old method involving propane flames and such. As described above, the modern and safe method uses an electronic sniffer.

[Tom L.]

Re: AC leak detection

The BEST leak detector for CFC refrigerants (R-12 included) is a Halide torch. Sadly obsolete and I doubt that most have one, I've held on to mine for the work I do and sadly I use it less and less.

Moving on, there are many electronic leak detectors on the market and most work OK but using them is a learning curve. Most will detect dust as a leak creating false positives so caution is advised if you go that route. When using my electronic detector I always confirm it with soap bubbles, an old but accurate leak detector. I used "Big Blue". In a pinch Windex works pretty well. Once you've located a suspected leak with the electronic detctor, spray a bubbly solution on it, wait and confirm.

In general a great approach except for compressor seals. When dry of oil they often leak and will seal up with usage. Once back in service during the cooling months those leaks will seal up, the down side is a loss of refrigerant. Hope this helps. Good luck!!

[Larry M.]

Re: AC leak detection

The BEST leak detector for CFC refrigerants (R-12 included) is a Halide torch. Sadly obsolete and I doubt that most have one, I've held on to mine for the work I do and sadly I use it less and less.

Moving on, there are many electronic leak detectors on the market and most work OK but using them is a learning curve. Most will detect dust as a leak creating false positives so caution is advised if you go that route. When using my electronic detector I always confirm it with soap bubbles, an old but accurate leak detector. I used "Big Blue". In a pinch Windex works pretty well. Once you've located a suspected leak with the electronic detctor, spray a bubbly solution on it, wait and confirm.

In general a great approach except for compressor seals. When dry of oil they often leak and will seal up with usage. Once back in service during the cooling months those leaks will seal up, the down side is a loss of refrigerant. Hope this helps. Good luck!!

Tom:

Agree with "the learning curve"..............

The electronic detector can find compressor seal leaks and evaporator core leaks that a soap solution cannot. The TEK-MATE is not real sophisticated and is reliable. Not fancy or cutting edge, but works. That is why I bought it. What type/brand are you using??

Larry

[Tom L.]

Re: AC leak detection

A unit made by CPS products that I've had for many years. Simple and effective, there are more modern ones out there but I'm used to the one I have so I stick with it. Either way I always back up the electronic unit with soap bubbles to confirm.

Frigid here in the North east and just got a service call. The condensing unit is on the roof so I'll be exercising my tester in the cold. Have fun!!

[William F.]

Re: AC leak detection

Thanks for info about electronic leak detectors. But he reason I'm asking specifically about possible problems with using the "dye" method is: My tech used dye to find a leak which turned out to just be a bad shrader valve where you would attach test equipment.(Wish we had started with soapy water-bubbles) New valve and all ok for about a mo when my original to car R12 system quit cooling. Pressures indicate system not letting R12 return to compressor. Dye stopping up POA or the screen in expansion valve or just a coincidence with original to my '67 POA going bad?? Any body else's experience with "dye" good or bad?

[Tom L.]

Re: AC leak detection

The dye shouldn't clog anything, never experienced a problem with it. I'm not a fan of the stuff for a few reasons and never use it.

Does the port on the POA valve show pressure? I believe that is evaporator pressure, if you see no pressure do then I'd lean towards the POA valve being an issue. Pressure wouldn't get into the evaporator if the expansion valve was bad. If there is no pressure in the evaporator I'd be leaning toward the expansion valve as the issue. I'm of course assuming that these pressures are taken when the compressor is running and you have plenty of pressure on the high side. Good luck!

[Dick W.]

Re: AC leak detection

Many moons ago I started with the halide torch (still have it just in case). With the advent of the electronic sniffers I quit using the torch. Occasionally I will add dye to one that I cannot sniff out. There is a place for all the above, depending on the situation.

[Christopher B.]

Re: AC leak detection

I've been repairing A/C systems for over 30 years. Dye will not have any detrimental effect to any A/C system UNLESS too much is injected. The dye is suspended in system oil and is injected on the low side. If too much is injected it will coat the evaporator and affect it's ability to absorb heat. 1/4 ounce is all that's needed on most systems.