We have a 35/36 truck radiator in our 37 coupe . Noticed the patch for the old filler was a little discoloured before we left on a 9 hr return trip , a lot worse now. 13lb cap been good for 15 years but now getting ready to blow I fear. Surprised no real water loss. What is the best way to resolder this without removing the radiator. I hate , hate removing this radiator, might as well put my hands on the bench and beat them with barb wires.
I’ve found that solder for circuit boards has a fairly low melting point and works for this type of problem, obviously need to clean the area thoroughly before hand and apply lots of paste, I use an acetylene torch with a medium tip, I find that to work best as the flame is big enough to get some heat into the area and small enough to localize a spot to reach flow temperatures without compromising the rest. Best to have the rad empty and rinsed thoroughly also.
I once witnessed a top tank fix, after I stupidly ( youth ) installing a new battery, and letting the wrench span from plus+ to top tank. My cohort, a post retirement Packard mechanic, simply clean, clean, clean the area, after the hot anifreeze stopped leaking. drained some more, then used a bernzmatic and regular whatever solder. The customer witnessed the whole event, and returned, never to complain. [Yes, I learnt * Neg, 1st off last on *]
Those 37 radiators should have no more than 4 lbs. it’s surprising it held together for you. What did you do to pressurize the system at the overflow tube? I’d suggest doing the correct repair. Remove the radiator and have it checked and repaired. Or replace it. Yes an expensive situation.
Buy proper solder and flux, a lot of the Chinese stuff is absolute ****e, someone explained the different formulation to me once but I can’t remember the details.
The correct repair is to take a torch, melt the solder and remove the old patch. Be careful with the heat as you do not want the tank to get hot enough to melt the solder between the tank and core. Once you get the patch off, cleen, cleen, cleen. Use a torch and a wire brush, even some soldering acid. Tin around the hole and the patch, then put them together, heat and add solder around the edges. You need acid core solder. We used to buy some tinning compound that had solder and acid mixed.
Originally way back we did have the original 37 radiator with a 4lb cap and huge top tank, That is why we used a 35/36 truck radiator with the small strong top tank . 13lb would blow apart a regular 37 tank. I imagine you can see the modern filler cap with a pressure relief we fitted that goes to a catch can. I have had the radiator out a couple of times in the past 15 years and it uses up the full vocabulary of naughty words. A job I want to avoid if at all possible. [ QUOTE="Petejoe, post: 15734131, member: 1077"] View attachment 6558953 View attachment 6558954 Those 37 radiators should have no more than 4 lbs. it’s surprising it held together for you. What did you do to pressurize the system at the overflow tube? I’d suggest doing the correct repair. Remove the radiator and have it checked and repaired. Or replace it. Yes an expensive situation.[/QUOTE]
4lb cap on mine. They don't require more, and you can do more than just damage the radiator, the water pumps (unless they are new builds) can leak as well as they weren't made to handle that kind of pressure. I would remove the radiator and have it properly soldered and tested but consider a new radiator cap.
Thx @Petejoe ,haven’t had a problem,yet, with the pressure but looks like I am now. So you’re saying don’t take shortcuts. I want a recovery system,so what pressure do you recommend. I put this new radiator in ( well recored original) back when we had a super charger on it. It’s not a new build now after 15000 miles.
2-4 pounds max pressure release valve attached directly to the end of your overflow hose. No need for a recovery tank. I’ve used the simple 2 lb brake pressure relief valves and they work perfectly. Haven’t added water since last year.
Radiator work Like mention above,, Clean Clean Clean , & heat control . Flux & good Quality solder & hand held butane torch Like 3 inch long Will do the Job. To cold will puddle up with resistance To hot will roll right off , When correct temp it will flow right in Like a suction.. Take & practice with 2 Tin can's So you can get a Ideal how much heat & how much solder to feed / use . When done right Saunders pretty strong. Cleanness & Heat is the trick !! Im in my mid 50s learn to fix ,Rod out , R&R tanks , & recore from my grandfather's radiators shop. Around 8 years old
If I was short on time, I would "shade tree" the thing. Clean REAL well. Use J B or some such. Paint. Just might even forget the repair was even done after a couple years! Actually, the pressure cap does not CAUSE the increased pressure, it allows the coolant temperature to increase without boiling.
If it's just weeping or seeping a bit and not putting out a stream of coolant, and you're not anxious about doing a more permanent repair . . . Pick up a package of GM coolant sealing tabs at your local dealer. They're small tan pellets usually sold as six on a blister pack. GM recommended them for use in certain Cadillac engines that had a iron/aluminum block and head combo after replacing the cylinder heads to stop weeping that often happened after re***embly. This might buy you a little time, or more, before making a more expensive repair.
Tried that once when we were 10hrs from home and a 4 hr ferry ride. I commented on how rough the roads were . Oops forgot that they had had couple of very nasty earthquakes 6 months ago . Used “seal well “ black cubes , boiled them up in the motel added to a hot radiator, nope still leaking. . Had another radiator leak in a different car 8 hrs from home. A small town with no help, luckily a vendor at the show had some Rislone , like small suspended copper flakes , saved the day. I don’t really like adding goop to my radiator as what else will it do ??
Hello, That is amazing that nothing has happened in the years you have been driving the 37 hot rod. Despite the cost of a new one, that is one thing that would have been replaced years ago. The first thing on sees when opening the hood is the radiator. The nice detailed flathead motor compartment, as nice looking as it is, becomes secondary. It may not be a show car, but every time you open the hood, that is staring you in the face. My flathead 40 Ford Sedan Delivery as a teenager at least had a nice compartment painted all black and everything was as it should have looked. Despite a stock motor, when the hood got raised, at least everything was detailed and nice looking, even though it was a stock motor and compartment. When my wife and I got our 327 SBC project car started, the radiator was jammed in its place and was discolored as if someone had done some work on it and forgot to paint it. We bought it partially finished and it showed various parts that were left as is. It was terrible in handling and braking and that was our first concern. Months later, it drove like a new showroom car. So, now, the hood was raised and the first thing we did was to take out the radiator. Wait, why take out the radiator? We also had to replace the water pump, so we killed two birds with one stone. we spent some time sanding and detailing the whole radiator out side of the sedan delivery, although we could have just painted it while it was still in place. It was the first thing seen as we opened the hood for oil, water or battery work was almost the same huge “black thing.” Jnaki We were not preparing it to be a show car, but it takes pride in having a nice hot rod for our own road trips and ownership. Did it matter that no one else had a 327 powered 1940 Ford Sedan Delivery? After it was totally drivable, no one could get my wife out of the driver’s seat for her usage, whether it was visiting friends or a quick trip to the grocery store. She did not raise the hood, but she knew it was nicely done and was proud that it was “her” (our) hot rod as 20 somethings. Ha! For you, somethings just need to be replaced and not re-welding a new plate over the old one, unless you feel that is the lowest cost since you have had luck in the past usage. But, aren’t you tired of telling folks why there is a huge, ugly patch on your radiator, even if it is patched, again? The radiator has to be reliable for all purposes. No one wants to be the guy sitting off the highway pavement with the hood up and smoke/water pouring out of the compartment…YRMV
In my opinion replacing the radiator is the best solution as @jnaki said you see the radiator every time you raise the hood. However that’s an expensive option and you stated something to the effect that you’d rather beat on your hands with barb wire Ooch. Second best solution is to remove the patch clean everything really good and solder back together. Third @firstinsteele talked about using JB weld. Definitely a backyard type repair. I can tell you the JB weld will hold up well, I’ve repaired a few radiators with the stuff. I thought it would be a temporary fix until I had time to remove and solder correctly or take to radiator shop, which is what I’ve done with most, except one DD POS I drove until the car was ready for the s**** yard. Personally I don’t think the patch itself looks bad, a little paint and it’ll look good. Dan
Just saying , with a good cleaning , Heat That can be repaired & look more presentable , close to non-visible repair In vehicle wants you know how much heat needed with one those good quality Hand held crack torch . Or jewelry torch set's
I wonder if silver solder would wick in and seal it up? Might be worth a shot if you’re going to remove the patch anyways.
I’m not trying to recreate the show car , just advice on a repair. It was replaced and recored with a new a copper core 15 years ago. Probably should have done a little panel beating on the top tank . The mess only appeared last weekend. We have owned the coupe 40 years. It did win best coupe , best flathead , best paint in its first national hot rod show.
Contrary to some of the opinions in this thread, that is a cheap and easy fix for anyone who knows how to solder. Melt the patch off and CLEAN, CLEAN CLEAN. You don't need to clean the areas where the solder is still adhering well, but the area where the leak is should be sanded to clean br***. Then spread flux, and "tin" both the patch and the radiator, heat and add a bit of solder to flow in between the radiator and patch. If the surface of the radiator and the patch are both mirror flat, you will need very little solder to create a long-lasting repair. If you were in my part of the earth I'd invite you over to have a couple chilly drinks and I'd spend 30 minutes fixing it for you.
Thanks for the straight up reply @Ebbsspeed , hmm adult refreshments, very tempting indeed. The car has never overheated even in heavy stop go traffic. I won’t be intimidated by a gauge. I have oxy , and a map torch, probably the oxy with a fairly small tip and low flame . I used to have an old solid solder stick ?? Probably resort to a 2” rotary sander ,wire brush on a drill, sand paper and flux it, tin it. Hopefully the solder I have now is ok. The radiator guy in our town retired. I still remember my first and only attempt at a radiator fix ,40 plus years ago . Heading off to the drags on the other side of our island, noticed a small top tank leak ( car long gone) solder it up . 1/2 hour from home a big geyser as it split the seam .
The good news is that I called my recently retired radiator spe******t and I get the area clean and ready and he will com a put it on . Nice.
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