I have a small leak at the top of my air conditioning condenser.

Last summer, I tried patching it with JB Weld. They do advertise as working with all metals, but I suspect it failed to hold because it doesn't bond well to aluminum. I could get enough refrigerant in to get some cold air, and then the patch would blow. By the third patch, it seems the hole was getting bigger because it blew very easily. (So, I guess it must have had enough hold to pull some more metal out — d'oh.)

How would I go about patching with a torch? My closest experience is with brazing on brass. Just getting a little aluminum plug welded over the tiny hole shouldn't be too bad.

What kind of torch, flux, and rod would I use? Is there anything in particular to know about condenser tubing?

  • Is it in a crowded spot or is there enough room to put some strong hose material around it and secure with hose clamps? Commented Jul 9, 2011 at 22:27
  • It's at a bend in the pipe next the side support brace. The pipe winds tightly back and forth through tightly packed radiator fins, so I don't see that kind of fix working anywhere on this kind of condenser. Commented Jul 10, 2011 at 1:30
  • This was helpful to hear that the repair kits are generally temporary and replacing the condenser is the right way to go. The cost difference is about $100.
    – user18840
    Commented Jun 5, 2016 at 18:07

2 Answers 2


I think most pros will tell you not to bother trying to patch a condenser leak, just replace it. While that's not always an option, it's definitely an option you should consider first.
Can you source cheap second-hand unit for your car? Unfortunately condensers and radiators are often damaged in car accidents so second-hand units can be a bit dicey, so make sure you check it thoroughly and try to get a warranty with it. Obviously you could also try sourcing a new OE or aftermarket unit as well.
Your next best bet would be to remove the condenser yourself and take it to a radiator repair place and see if they're repair it for you. Removing it (and then fitting it again) yourself will save paying someone for the trouble. A radiator place probably won't charge much for a repair, assuming they think a repair is possible, as it shouldn't really take them very long. It usually takes a lot longer to get the unit out of and into the car than it does to do the actual repair.
Failing all that, you could try to do the repair yourself (which was your actual question I know). I'm afraid I know very little about this sort of welding so I'm not qualified to answer, but if you search for radiator repair/welding you should find plenty of info and radiator repair is pretty much the same as condenser repair. And hopefully someone with welding skills will chime in here with some more info for you.

  • That is what I've found from asking around. (Actually just talked to a radiator place yesterday!) The cost isn't the replacement unit, but rather the removal, reinstallation, flushing, and redoing seals. Welding without removal is not an option because of the oil inside the condenser. Perhaps I should ask another question about the importance of each of those itemized steps… Commented Jun 3, 2011 at 23:13

I think that it would be best to replace it, they are not expensive for aftermarket parts. A good used one would be better than patching it. For best results, you will need to pull a good vacuum on the system to eliminate any air or moisture in the system before charging. It would be best to have it done professionally to minimize release of refrigerant into the atmosphere.

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