Oxyacetylene Welding Radiator Leaks


Is it appropriate to use an Oxygen-Acetylene welder to patch radiator leaks? If so, what kind of welding rods are used?

I understand that certain metals cannot stand up to the high heat. So if not, what types, if any, of welding equipment or processes are customarily used by the pros? (the pros dont want to tell me)


You’ll burn a hole through the radiator this way.

Brazing might work (except on the plastic bits), but welding is too hot.


So what method is commonly used by the pros? JB Weld, which has worked on many high-temp applications in the past, has not worked in this instance.


What Make, Model, Year vehicle are we talking about? What type of radiator? I know a brass radiator can have holes and breaks brazened, which has been a typical repair method for ages. But a more modern aluminum radiator with plastic jugs cannot be repaired this way. Typically, if the aluminum core is damaged, it is best to go a replacement radiator. If the plastic jug, or tank, is leaking, it can be replaced cheaper than a new radiator.

If you give us a bit more info, we can help better.


I believe it may be aluminum, but some kind of METAL radiator for sure. Im not willing to spend more than say, 80-bucks to resolve this. The salvage yard wants only $45, with core (but Im not taking more chances).


Service and repair on brass radiators was done using solder and I think acetylene/air. But solder will not work with aluminum. You might get away with aluminum braze but I have not had much luck with that. Let us know what you try and what works.


Soldering is the usual procedure and it sometimes even works. You should get the new variety of radiator because your time should count for something, even if the materials don’t.


Heh, I guess I should have mentioned this, but Ive tried using solder with a propane welder. The main problem has seemed to be not being able to clean the tight spot the leak is at. Its where one of the cores connects and I cant get a small wire brush back in far enough where the connection contains rust, debris, or other corrosion, so the solder wont stick. My experience with oxyacetylene however is that if I get the surface hot enough the material will hold, however this method on a radiator is now ruled-out. Any further suggestions are much appreciated. Thanks again.


First, you HAVE to identify the base metal because the repair method is highly dependent on what metal you’re working with. AL is hard to work with because it naturally develops a nice protective oxide coating in a very short time. This can be removed mechanically or chemically.

Propane is going to be tough regardless because it doesn’t develop much heat compared to a torch or even MAPP gas. And any residual water in the tubing will inhibit proper heating. I would use MAPP over propane.

It should be easy to distinguish between copper and aluminum if you do a bit of scraping.


Actually, now that Ive scraped some, its copper. So do I try MAPP gas, and what type of welding rods? Any chemical to strip off corrosion in tight spots? Thanks again all.


solder is no good for patching a hole. Are you pinching off one pass and soldering it closed? If so then solder is OK. You will need silver brazing alloy with proper flux to patch a hole, and acetylene torch with a hot tip AKA turbo tip.