*Cringe* I've heard only bad stuff about cooling system "stop leak" stuff. Apparently, they should only be used when you want to get couple thousand km out of the car before sending it off to scrap. It gums stuff up. Bye-bye water pump, radiator (eventually), hoses, and so on... It'* only a band-aid solution. What you gain in the ease of the "fix" in the act of pouring stuff in, you lose with other adverse side effects...

I have heard the same things about stop leak additives. Anything that can clog a leak in my radiator that quickly can probably also clog the tubes running through the radiator and heater core. Maybe I'll just wait until something becomes more visibile. If it has gone 15,000 miles like this, maybe it will go 150,000 more
Thanks!

Yeah, I've heard bad things about that stuff too. On the other hand, I had used it before I heard all of that, and it worked as advertised. For a few years. Ideally, you should really just find and fix the source of the leak.

When you think about it, products like Bars Leaks are made to plug small holes. On cars as old as ours, your radiator and heater core passages might be reduced to small holes due to deposits already. You might end up plugging some small holes that you didn't intend to. Know what I'm saying?

All this is true.
But I have used this stuff sparingly to permanently plug minor gasket leaks.
The trick is to start with maybe 1/4 bottle and not much more.
I don't know how minor your leak is but you should not use it if you are not comfortable with the product or have fears about adverse effects.
In my own case I have found the claims on the bottle to be true and this stuff is factory installed on many auto assembly lines to take care of minor assembly leaks.
Its been around since 1947.
Again the best advice here is what was previously mentioned.
Find and locate the source of the leak and repair it.

I know of one person that did not want to use that stuff cause it closed everything else off. So, get this, he used a tablespoon of regular pepper. He had more than one leak in the radiator and didn't want to change it cause he changed so many other things on that van.


It would last a few months and if he noticed a bit of leaking he would use another table spoon or two. Not sure what is in pepper that would do that but I figure it is safer than the stop leak since stop leak as those pellets of stuff that seals off the holes.

A lot of things will clog a leak, there are a lot of myths out there too. I have heard of putting a raw egg in there... never tried it. I have tried horse manure once and it worked but it was in an old jeep, and it was the best option around at the time. Since most coolant leaks are very small, anything that is will maintain some of its structure in the hot temps will clog a leak sooner or later... just a matter of the side effects, like stinky hands

Just went through this with son'* Grand Am. Plastic radiator tank was leaking. JB Weld "Quickset" after cleaning with carb cleaner and sanding a bit seems to be working.

There was an old wives tale about putting rice in the water to seal a leak but may have been from cars of the '20s.

Myth Busters did the egg thing.. and it worked flawlessly.


-justin