[Richard]

I have not had good results with replacing my radiator. I replaced it in 2017 with one obtained from the original supplier. It lasted two years before leaking slightly at the tube header interface. I replaced that one with a core obtained from Rocore. It lasted three years before developing a similar leak at the tube header interface. 

I spoke with the original supplier who was not interested in making a heavier duty core for concerns over cooling efficiency. 

Long sigh. The engineer’s definition of insanity is doing the same thing over and over but expecting a different outcome the next time. The original supplier pointed me in the direction of Thermal Solutions. On their website I found they manufacture a heavy duty core where the tubes are tig welded to the header place instead of the conventional soldering. Like all the core manufacturers they do not sell directly to the public, so I asked them to give me some names of outfits within driving distance who they dealt with. I used Complete Radiator in Orlando, and was absolutely thrilled with their knowledge, service, and pricing. 

I went with Thermal Solutions UltraFuse design https://www.thermalsolutionsmfg.com/wp-c...uty-05.pdf. There are some things of note that I do NOT have real world data on. Obviously, I do not know if this will end up being a more robust solution. Second, the UltraFuse core used less rows of tubes, five instead of six, in the original, but the tubes are 5/8 wide instead of 1/2. And then the fins are V fins in the UltraFuse as opposed to straight fins in the original. I was assured by the radiator folks the UltraFuse design had MORE cooling capacity than the original but that real world data will have wait until the first hot day mountain climb to know for sure. Test drives in flatland Florida on a 90 OAT day did not result in any fan activation, and the engine temp stayed right at the tstat opening temp 196. That is the same result I would have seen with the original design. 

The removal was aided by none other than Bikestuff, and the install by another guru Russ White. Two things are supercritical when removing or installing. One, a work surface such as a lift table to help get the mechanic in and out of the “hole”. And more importantly, a helper to hand items to mechanic in the “hole”. It takes my decrepit bones a good five minutes to wriggle in or out of the confined space. So Mucho Gracias to Bill and Russ. 

I will report back on the longevity as I accumulate miles and hopefully years. I will also report back on cooling performance after a mountain workout.

[Gnawrocki1]

Glad to hear you got this radiator in before your big trip.   

Hope you have a safe trip this summer!

[Richard]

Thank you, no way I was striking out for Alaska with a known problem, no matter how small, with a critical system.

[Deper10]

Good Luck with your new radiator, sorry to hear the last one only held up a few yrs but glad you caught it before Alaska trip.
Take Care

Dario

[360]

Great info on that radiator and glad to hear you put Bill to work!

[BusNit]

That really sucks but at least it wasn't something to happen while you guys were already on your trip.

[kaptain]

I have not had good results with replacing my radiator. I replaced it in 2017 with one obtained from the original supplier. It lasted two years before leaking slightly at the tube header interface. I replaced that one with a core obtained from Rocore. It lasted three years before developing a similar leak at the tube header interface. 

Thank you for sharing your experiences, Richard.
I am just curious -  I don't know how difficult it is or possible, but have you looked into the leaking spot and thought about manually TIG welding the tube and the header interface instead of replacing the whole radiator unit? Perhaps the tube and the header interface are too thin, too small space to weld?

After watching the video on how radiators are made, I realized welding the soldered joints is nearly impossible. However, radiators are not too hard to rebuild. 
See how people in India rebuild their old radiators. https://www.youtube.com/watch?v=kEwQVUjsQwY

[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.

[Jack Houpe]

Good info but after looking at the radiator and how tight it is I would have to hire that job out, my body is falling apart. I wish you and Rhonda a wonderful trip!

[77newell]

A few thoughts/questions.

Is the general location of the leaks consistent or random?

The mass of the radiator is carried somehow between attachments top and bottom, suspended at the top, held up at the bottom. And thinking about the total mass, including water, being jounced around going down the road is really complex. It’s not clear to me how the weight is carried and how the horizontal loads are carried. There are dynamic loads in both directions when the coach is moving.

Richard’s statement about flexibility lead me to wonder about flex caused by the drop in pressure by air as it is sucked through the core. Given the area it wouldn’t take much drop to generate considerable force that probably peaks in the center of the fan disc.

I think I recall this previously coming up, but how are commercial bus radiators constructed, the tubes oriented, and mounted. It may be useful to talk with a bus repair facility that works on multiple brands, find out which has the least problems and then dive into the details that explain why.

No need to respond to these thoughts. I offer them as food for thought.