[Richard]

Joe, I have tried. And I have had radiator professionals try. Here is the challenge. On this particular leak, I could not get it to leak unless the radiator was hot. While the radiator was in the coach, I both pressure and vacuum tested the radiator. No leaks, no loss of pressure. After I removed the radiator, I made a second attempt at finding the leak. I sealed off all the openings and pressurized to 15 psig. No leaks overnight.

Why drag you through that? I had no confidence in any repair, because if I couldn’t find the original leak, there wasn’t a reliable way of knowing if I had a fix other than reinstalling in the coach, refilling with fluids and going for a drive. The guys at the radiator shop told me, they rarely do that kind of work anymore because it’s not cost effective. Keep in mind, the tanks have to be removed, reinstalled with new gaskets, and then the radiator is submerged after every attempt. I hate to admit how nutty I am, but I spent some time on figuring how to use my beer brewing equipment to circulate hot water in the radiator. I nixed that idea for fear of contaminating the beer equipment with ethylene glycol. I even went so far as to look into temporarily repairing the Aquahot engine preheat loop to provide hot water for the leak test.

I am not throwing shade on your idea. I had the same idea. I played on the bench with different solders, fluxes, and torches. Even going so far to buy a micro oxy acetylene torch to be able to work on small areas. I saw that video also and said how hard can this be. I am aware of a few people using a TIG setup to heat the solder in small areas, so I thought about that approach too.

It might have been more cost effective for me to repair the radiator, but it certainly had the possibility of being a huge time sink removing and reinstalling the radiator several times because I had no way of knowing if I fixed the problem short of a full reinstall.

Adding to my decision was the fact that I had tried to repair one of the previous leaking radiators. I could make it bubble to see the leaks. What I discovered after two days playing was trying to spot repair the leaking areas only moved the problem to adjacent tube junctions. I surmised the only way to repair it at the time was to resolder the entire end.

I kept the leaking core. When I run out of things to do around here, I may get out the torches and play around again.

And the last thing. When moving the old core about, I was surprised at how flexible it is. Hmmmmmmmmm, the flexibility was a shock to me. It got me to thinking about why we have so many problems with this radiator. If the core is flexing in conjunction with thermal expansion it would stress the tube header junctions. I have a working theory. If you look carefully at the construction of the structure that holds the core, the core has tanks bolted to each end, and top and bottom steel rails bolted at the corners. The point being the framework that holds the core is not necessarily a rigid structure. The bolts are only tightened to about 12 ft lbs to keep from squeezing the gasket out of place. If mine has to come out again, the structure that holds the rad will get diagonal reinforcement.