virtue4u

I discovered a small radiator leak at the top tube junction on the driver side. Is there any product that can be applied externally to help seal a radiator leak? If not, what is the best additive to add to the coolant that will help stop the leak but without damaging the rest of the cooling system? If you have strong feelings against such products, please advise. I realize that all such fixes may only be temporary, but I would like to give it a shot before replacing the radiator.

Larry B.

Mine leaked at the exact same spot. I used a product called "Bars Leak" and then I "painted" a small area with a two part urethane adhesive. That worked for a couple of years. It is only a band aid at best. My leak was very slight.. more like a seep.. I've had mixed results with stop leak products and you will never really trust you car. You will end up recoring or replacing the radiator anyway as I did. You do not want to be at the mercy of an out of town shop to do the job. It's difficult and expensive.

MIKER

Like silvervetteman, I too have had good luck using BARS LEAK in the past. GM sells a sealant. It's tablets made of walnut shells etc. I don't know how well it works. There are probably a dozen different products to choose from.

A few years back we were going over Wolf Creek Pass (el. ~13,000 ft) in my Dad's motor home and the water pump failed and began to leak BADLY. We caught a ride into town, purchased a new water pump and a little bottle of (forgot product name) aluminum oxide stuff. We poured the stuff into the radiator, filled it with water and planned on nursing it down the pass to town so we could change the pump. After arriving in town, we found that the water pump was no longer leaking!!! We didn't change the pump until returning home to Texas, not because it started leaking, just because it needed replacement.
Sorry to be long winded but the results from using that little bottle of aluminum oxide stuff amazed us.

GaryS

A stop leak product may work but, as has been said, this is a band aid that may leave you stranded later. Fix it permanently by visiting a reputable radiator repair shop and get their opinion.
Gary

Smokehouse69

The leak is probably an easy one for a radiator shop to fix, I don't think they'll even have to pull the radiator. I had a leak like that fixed on a 73 Pontiac Ventura (Nova Clone) and the shop just drained fluid until it was below the leaking area, cleaned the area and brazed it shut. It took about 15 minutes total and cost me about $10.00, of course this was nearly 30 years ago, it'll probably cost $50.00 for the same thing today. :cry

page62

It depends upon which part of town the radiator shop is in! I think some places around here have gotten cheaper... :D

Missileman

The bad thing abolut additives is they coagulate inside of the water passages. Their thermal conductivity is substantially less than steel, and I have even found ***** of additive (golf ball size) at the inlet to the lower hose reducing flow to the water pump. If you need to get down a mountain or drive to the used car lot additives are the way to go, but I would not recommend them.
As for your leak, buy a roll of ACID-CORE solder and a portable propane torch. I have fixed hundreds of radiators with this and never had a return.
K & M Restorations.

virtue4u

I was wondering whether brazing was possible. I have also heard of an epoxy ribbon. Has anyone heard of something like that? I am trying to avoid internal additives even though the seep is extremely small.

virtue4u

After reading all the suggestions on this and other forums, I see little reason to ever use an internal additive to fix a leaking radiator. The most promising external fixes are as follows:

Solder/Brazing
Devcon Epoxy Putty

Has anyone ever used Devcon products? It has military applications for sealing water/fuel tanks and pipes. I learned of it on a Jag forum. I think I will try it because the soldering would probably require removal of the radiator to heat it up with a torch. I don't mind removing the radiator, but this product may save me some work.