JB-Welding Upper Radiator Seam
 

JB-Welding Upper Radiator Seam - anyone done this ? i have successfully used JB in the past to seal a cracked radiator (plastic part) on my '85 , when i couldnt afford a new radiator.....

this one started seeping after the second citric flush.....annoys me, i have to leave my cap loose now as well to not build pressure....

Do it and don't look back. I've repaired more than one radiator with JB weld, the trick is proper prep-clean the surface with brake cleaner and/or ether, and be sure to put some nice scratches in the surface for the JB to stick to.

Let it sit for at least 48 hours before giving it pressure. An incandescent bulb shining on it may help it cure faster.

Applying three layers of $100 bills also works very well. A tube of it is pricy though. :D

I wondering if the plastic cracks in one place from age and heat, there is the possibility of it doing in another spot?
I know when the finances are tight, we do what we have to do.

If it works and hold the pressure, good, I hope it does. I would be keeping my eye open in the yards for a new one. new one`s, or fairly new, do show up if you look for a while.

I tried to JB Weld a cracked plastic grill on my 240, and it didn`t stick very well. Different plastic, or I didn`t prepare the plastic good enough.


Charlie

How about using the plastic radiator repair kits that come with a piece of fiberglas cloth and a piece of sandpaper too, The liquids use to seal it get really scalding hot to melt the fiberglass and itself into the plastic.

are you talking about JB'ing the plastic to the aluminum? I doubt that would work...

My local jy charges $35 for a radiator

I'm in the source a JY radiator camp. JB weld has its place (I use it a lot) but a plastic-aluminum joint with high temp deltas, I think is going to be a short term fix at best.

That being said, a tube is $5, and the radiator is bad anyway, so what's the harm? Silicone might be another option.

As I read it, he just has a minor leak-not a big gaping hole, which JB weld would be perfect for sealing.

I would first try AlumaSeal, which is powder you shake into the coolant. You need to put in the top hose, not the remote reservoir. It has worked for me on several cars to seal small coolant leaks, and it is more benign than the silicate solutions which can clog your radiator.

I wouldn't put any of that stuff in a car I planned on keeping. I have a feeling the heater core will be blocked in no time.

I've used the AlumaSteel a lot over the years, also the small rubbery black ball sealant. Never had a problem with a heater core getting plugged.

Epoxy does work for a bit but may fail since it is less flexible than the plastic tanks.

Plastic tanks fail a few ways, Pressure cycles and degradation of plastic.

Everytime the cooling system builds pressure, the tank balloons out. The constant flexing eventually leads to a crack. Filling the crack stops the leak but does little to keep the tank from flexing. If you do make this type of repair, be sure to get epoxy in the crack and spread it around as an reinforcement. JB weld is more of a putty and seems to need help sticking to the surface.

Brass tanks aren't immune to flexing either.

When plastic degrades over time, epoxy only works in the very near term as there just isn't enough stuff left to glue to.

I have used JB Weld on radiator tanks with poor results, as in, it worked for a few months and fell off. I am with the "radiator sealant" group. I have Barrs Leaks in my 606 now. It has sealed a head gasket that was leaking water to the outside, for the last two years. I like this brand as I can mix it with removed coolant and allow it to settle for a few minutes before pouring about 3/4 of it back in. This allows the removal of the large particles that might plug anything important and would certainly settle out in the block. I have never plugged a heater core, that I know of. About 30 years ago some of the manufacturers of antifreeze sold a coolant with leak sealer in it as a value added. I'm guessing they stopped because brown sludge on the bottom of the jug was off putting to those who forgot to shake the jug.

I have drug more than one BMW in off the interstate with cracked plastic cooling system parts that have been successfully repaired with JB Weld radiator repair material and sent on home. If you are in a bind then I say use it. Otherwise the most reliable, long term solution is to replace the radiator every say, 250k miles.

Epoxy
 

I once used a syringe (no needle of course) to inject epoxy into a radiator crack. This caused the epoxy to "splay" on the inside, forming an nice seal on the interior of the crack. Never did leak again.

It's too bad you only got 200K miles out of the first one. You suppose it's still under warranty?