Radiator pin hole / what would you do?
 

Going through a checklist in anticipation of firing up the 54F100 and discovered a small pinhole in the radiator as I was flushing it. The truck has been sitting for 6 years and I'm just hoping to get it fired...it will probably need a good going through later but now I'm just hoping to get it to run. The fluid was quite clear, no discoloration or rust present. I was surprised how clean it was. I was also surprised by the small leak-about the size of a pencil lead-at the bottom portion of the radiator. Not sure of the technical term but it was below the "fins" in the solid portion of the radiator, 2 inches above the petcock, but on the front side. Any suggestions on a short term fix so I can get it fired? Is it something that I should consider repairing as part of the longer term rebuild? Looks like a new radiator is around $330. Like to hang onto the original if practicable? Would appreciate your thoughts...

In the short term, just to start the truck, you might be able to solder the hole closed. You might also check some local radiator shops, I've found that most of the time radiators can be repaired/ rebuilt for a fraction of the cost of a new one. Plugging/ soldering the hole closed may work for a while, but if the metal was thin enough to open up there, then you have no real way of being sure how solid the surrounding metal is. It could be just as bad. Have you checked the antifreeze level? Most modern coolants have a rust inhibitor in them.

Whatever you do, don't attempt to use any sort of 'stop leak' that you just pour in the radiator. Yeah, they'll stop up the hole, but given enough time they'll stop up everything else, too. I worked on a truck once (newer F-150) that the guy put a bottle of Stop Leak in. Wound up putting a new heater core, radiator, and thermostat in it, along with having the water jackets in the block chemically cleaned to solve an overheating problem.

Try a local radiator shop. They can probably fix you up for a good bit less than a new radiator.

^^^---^^^

Absolutely right! The black goo is bad stuff!

IF the surrounding metal is OK, I'd guess you could drain the radiator, and solder a patch over the area (like a 1/2" x 1/2" square). You might want to pull it, it would be easier but kind of against your goal of just running it. If it leaks noticeably without heat and pressure, it will be pretty substantial while running.

LiftTech hit on a lot of good points. Maybe the right fix now is going to depend on your long term plans for the cooling system. But if you want to keep the original radiator and save the $$$ then you'll have to figure out just how thin it is first. One avenue is to pug the hole, fire up the truck and see if an more leaks develope. But trust me, th elast thing youwant to do KNOWING you have to repair the rediator eventually is to put the stop leak in it - it's going to cuase problems and probably not plug the hole.

After the local radiator shop fixed my pin holes (I had to take it back three times to get them to do it right) I decided to do it myself.

These radiators are VERY thin, and any kind of torch will blow right throught them. There's a very small margin for error between the solder melting temp and the brass melting temp at that thinness. Also, engine coolant is about THE biggest pain to try and clean and keep cleaned off of something. You've got to be pretty skillful to solder on a radiator, get it to stick and not make it worse.

So, if you aren't that good at soldering, try this. Drain the cooling system. If the hole is fairly accessable, remove all the paint from around it in an area about the 2" square. Use 360 grit wet/dry, a soft wire brush or acetone. But, it's got to be spotless. Then make sure the pin hole is dry from the inside by getting a vacuum cleaner and cupping the hose in your hand and over a PORTION of the filler neck. You want a VERY slight vacuum - maybe a pound or two. Dab the hole with acetone from a model paint brush while doing this. There is another way to create this slight vacuum without the use of a mechanical device, but I won't suggest that procedure on this site. Use your imagination and don't let anyone see you do it.

When the pin hole is completely clean and dry, wipe it with a clean paper towel moistened with acetone or laquer thinnner. Make only one wipe then use a dfferent part of the towel to wipe again - about 5 times.

Cut a small (about 1" square) piece of fiberglass cloth, and mix up some 2 minute epoxy. Spread the epoxy on the glass cloth but DO NOT brush it on the pin hole. Wipe the pin hole one last time with acetone of laquer thinner; then, with your finger, stick the saturated glass cloth over the pin hole and pull your finger straight off. Do not move the glass around or from side to side at all. If there is any residue from the coolant (yes even after all that cleaning) still in the hole, you don't want to spread it around.

Let it dry 24 hours and it should hold long enough for you to fire up the truck an possibly put a few miles on it. But if what you are describing in not at a seam, I'll bet you will have more holes when you get it up to operating temp. At least this way you will know where you stand before running the thing into the radiator shop 10 times.

Good luck,
J!

If you're looking for a short term fix you can try a cheap fix race car driver's use at the local circle track and I have been told it was done in the days of the Model A. Dump a can of black pepper in the radiator. The circle track guys do it because they aren't allow to use chemicals in their cooling systems in case there's a accident they track owners don't want a chemical mess.

BTW, I had a bad leak in the core of my radiator so I plugged it with a wad of two part epoxy, that didn't quite stop the leak so I dumped a bottle of stop leak in. It stopped the leak and I haven't had any problem since. I too want to get a new radiator because the one I have has had numerous fixes that are evident. I just don't have the money right now for a new one.

The Pepper is a good quick fix, have used it many times. We used the Red Pepper, either will work, one table spoon is usually all it takes
Leave the Rad Cap on loose, and don't use a high pressure cap, 4 lbs. is plenty good, and just fill the Rad to the top of the core.
I have seen a lot of guys fill the Rad on the old Flatheads to the top of the Tank, that is a no no.
Thats why its called an Expansion Tank, for just that reason.:-X22

Howdy,


I have always fixed problems like that by buffing the area until shiny. Get some acid flux 60/40 solder and a small piece of copper sheet about 1/2 in dia larger than the hole. "Tin" the hole and the area around it slightly larger than the patch and tin the patch. lay the patch on the hole (after you shape the patch to fit well) and put the patch on and heat it with a big iron....and flow it all together. (don't use a torch....you might unsolder the whole bottom tank.

Epoxy might work too. everything has to be squeaky clean and dry.


Uh, I respectfully disagree,

Melting point

Brass 1724 deg F
Copper 1976 deg F
lead 621 deg F

Solder 60/40 has a melting point lower than lead.

Either brass or copper has a melt point more than 1000 degrees higher than any lead/tin based solder.

I will agree about not using a torch (propane torch) not because you'll melt the brass (it won't...the highest temp you can get with propane (not mixed with oxygen) is about 1900*F....)

You cannot localize the heat with a torch like you can with an iron as it only heats what it touches....and stops heating the work as soon as you pull it off


Cheers,

Rick

You gotta remember, the tank metal is going to be sucking away heat nearly as fast as you can put it in, too (that's why they make radiators out of copper/brass). I wouldn't hesitate to use a pencil-tip propane torch as long as it's away from the tank joint.

PS -- 60/40 melts at 370 F.

Yeah, the guys that do radiators for a living do it pretty well with either a natural gas torch or a propane torch. I've had pretty good luck with a gasoline fired torch to heat a big copper iron on it.

Yeah 60/40 melts at a pretty low temp. It's just if the hole is really close to a seam or where the bottom tank is soldered on you want to keep the flame angled away from the seam. so you don't melt it there while trying to do the patch.....

I'll probably still take my radiator to a local guy that has been doing radiators for years. I think he charged me about $150 to do my last one.

Man, prepare for sticker shock if you haven't been there in a while, especially if you need a recore. Man, the last time I checked around the going rate for a recore was $450+. I really need a new radiator for the panel but I can't afford dropping the money for one right now.

The only "upside" to the price of copper may be that aluminum is cheaper now. Doesn't necessarily mean an aluminum radiator is cheaper than copper, but the difference has closed.

This works on radiators and gas tanks(with gas in them too) in a bind.
Many times a pinhole has some meat around the leak. You take a decent size sheet metal screw and put it through one of those rubber washers used to repair the water fawcet. Coat it heavy with two component epoxt (5 minute epoxy) from hardware store. Screw this directly into the pinhole..it will seal and adhere quickly.It will fix leaks in rads and tanks.
shady tree mechanic

Yeah that looks great on paper, but unless you have a digital torch that you can dial in the absolute correct maximum surface temperature with, then you aren't dealing with simple paper temperature absolutes but rather the amount of heat applied in Joules (I like that name) over a given area for a given amount of time.

Long story short: unless you have a VERY carefully controlled, small, unforceful flame, (or the idea of a large iron is perfect) putting out just enough heat, you COULD melt through the thin brass before you get enough heat on both pieces of brass or to the solder to melt it.

Point was not the melting temperatures of metals but rather: unless you really know what you are doing as far a soldering radiators, either let someone who does do it, or use one of the other constructive suggestions that folks have passed here!

Soldering radiators and blowing hole in it while trying is one of those "this is a very unforgiving place to try to teach yourself how to do something you haven't done before"

And by the way, I know this because of the radiators I messed up. And, respectfully, a propane torch WILL blow a hole in a brass radiator - I've done it.

J!

I have soldered on a LOT of brass with a propane torch....radiator and brass sheet that I used in electronics equipment. I have NEVER been able to melt the brass with the propane torch. (I never really tried to either) I have always only used enough heat to flow the solder (using acid or rosin depending on what I was soldering) so I suppose cannot say you would never melt brass with a propane torch. IMHO, you would have to work at it....
Having said that, an iron always seemed to work best for me since I only wanted to localize the heat.

As far as a screw goes, yes that works well. only use a brass screw and just solder it into the hole (using an iron of course ;) ) after you screw it in.

Well that just goes to show you like my dad used to claim, I can always seem to do the impossible especially when it comes to screwing something up! I like the iron idea or the epoxy for a newbie!

Smiles!

Julie

BTW, where in "Western Wa, " Vancouver by chance?