Air Conditioning leak checking / finding information sharing thread

[Albrigap]

I have found that replacing both Schrader valves in the high and low service ports can help a lot.
Those can leak a lot and can easily be changed.
I am using mostly dye in my units.
It seems to work the best but then I use the soapy water after zeroed in on where the leak is.

 

[Ricko1966]

Timely post, I've got a leak I need to find on my motorhome (05 Kodiak chassis). Last summer I had a compressor failure following a leak, replaced the compressor, condenser, 2 of the 3 lines, evaporator, drier, and orifice tube so I'd never have to worry about it again. Drove it this spring, guess what, no AC... Initial dye test didn't show anything, I'm going to put in a can and try the sniffer.

Couple of notes: ALWAYS replace the drier if air gets in a system. Moisture in the air traps in the drier, when it saturates, the moisture can combine with the oil and form acids that eat the system alive. It's great $20 insurance if you care about the vehicle.
Another option that's not as common is to charge the system with dry compressed nitrogen. You can get a modern system to 500 psi for your soap test. Converted R12, you might stop at 400 or less. If you have a shop, then an ultrasonic leak detector unit might be a good addition as well, pressure it up with nitrogen and "hear" the leak, then vacuum it down and the drier stays dry vs using shop air.

And last, one of the better mobile HVAC refrigerants is actually butane (but don't try "converting" your own, there's a lot more to it), it's cheap and efficient and works well with the right system design, but can't be used because the government doesn't want people driving around with compressed flammable liquid in their car. Which is exactly why gasoline in a passenger vehicle is not flammable, and the oil mixed in with the 134a that lets loose under pressure won't create a nice fireball when you give it an ignition source. Oh wait, that might not be true...

I've had this argument with people before,it's not about driving around with butane or propane in your A/C it's about parking in your garage for the night while your A/C leaks 2lbs of propane/butane into your garage,which gets lit off by the hot water heater. Even better the whole car fills with propane first,because its an evaporator leak.IMHO propane,and butane are not a suitable refrigerant for an automobile. The risk in a crash I think would a momentary ball of flame at worst,in a drive under basement,etc. I can seea much bigger danger.

 

[SirRobyn0]

I've had this argument with people before,it's not about driving around with butane or propane in your A/C it's about parking in your garage for the night while your A/C leaks 2lbs of propane/butane into your garage,which gets lit off by the hot water heater. Even better the whole car fills with propane first,because its an evaporator leak.IMHO propane,and butane are not a suitable refrigerant for an automobile. The risk in a crash I think would a momentary ball of flame at worst,in a drive under basement,etc. I can seea much bigger danger.

I think you have the right idea. I'm not really even sure 2 lbs of propane in a garage is enough to cause anything to happen if it were to leak out. An evaporator leak and the guy driving it lights a cigarette, I can see how that could be a problem.

It's always seemed strange to me it's perfectly legal to convert a vehicle to run on propane, but we cannot convert the A/C system to use it. Seems ridiculous to me.

I agree propane and butane is not a good choice. Two reasons I'll add. Because it is more flammable, and because propane and butane molecules are smaller than R-12 or R-134A, the A/C hoses would need to be switched to barrier hoses, so the stuff doesn't literally seep out through the lines. Since no one makes premade barrier hoses, you'd need to pull all the lines off take them to a shop (or buy the equipment to do it) and have barrier hoses crimped on. Good luck explaining why you want them. Then the next issue is because it is so much more efficient than R-12 & R-134A it's going to turn any orifice type A/C system evaporator into an ice block, on anything but the very hottest days. As soon as that happens air can flow though the fins and that ice cold A/C becomes warm. If you continue to run the A/C like that you can do damage. So you'd have to rework the system to use an expansion block or figure out a way to monitor maybe with a temp probe somehow to trigger a relay to cycle the compressor when evaporator temps approach freezing.

Not to mention whatever fire risk there is. Also propane is poor carrier for the oil so the likely hood of compressor failure maybe increased. Basically I wrote a lot of words to say the stuff is useless as a quick pump in replacement.

 

[Hunter79764]

I think you have the right idea. I'm not really even sure 2 lbs of propane in a garage is enough to cause anything to happen if it were to leak out. An evaporator leak and the guy driving it lights a cigarette, I can see how that could be a problem.

It's always seemed strange to me it's perfectly legal to convert a vehicle to run on propane, but we cannot convert the A/C system to use it. Seems ridiculous to me.

I agree propane and butane is not a good choice. Two reasons I'll add. Because it is more flammable, and because propane and butane molecules are smaller than R-12 or R-134A, the A/C hoses would need to be switched to barrier hoses, so the stuff doesn't literally seep out through the lines. Since no one makes premade barrier hoses, you'd need to pull all the lines off take them to a shop (or buy the equipment to do it) and have barrier hoses crimped on. Good luck explaining why you want them. Then the next issue is because it is so much more efficient than R-12 & R-134A it's going to turn any orifice type A/C system evaporator into an ice block, on anything but the very hottest days. As soon as that happens air can flow though the fins and that ice cold A/C becomes warm. If you continue to run the A/C like that you can do damage. So you'd have to rework the system to use an expansion block or figure out a way to monitor maybe with a temp probe somehow to trigger a relay to cycle the compressor when evaporator temps approach freezing.

Not to mention whatever fire risk there is. Also propane is poor carrier for the oil so the likely hood of compressor failure maybe increased. Basically I wrote a lot of words to say the stuff is useless as a quick pump in replacement.

Yep, 100% not a drop in and I DO NOT RECOMMEND ANYONE TRY IT. That said, I don't think 1-2 lbs in a garage would cause a problem any more than 20 gallons of gasoline would. Or more than the 6 pack of coleman propane cylinders in the camping gear in the garage, or the multitude of other flammables that no one even thinks of that ride around in the car and get stored in attached garages. But, it really doesn't matter because no one will ever implement a large scale system, so its a moot point.

 

[Albrigap]

This is very simple.
If you want to run it, then do.
If you don't want to run it, then don't.