OT: Any experience with radiator stop leak products? (2024)

Do these plug up slow leaks on engine gaskets?

Yes, but some might plug up your radiator too. If the leaks are minor, I've used sodium silicate successfully on several occasions. Drain and flush system to remove all anti-freeze, add plain water and 1 pint sodium silicate to radiator, leave radiator cap loose so it does not build pressure, get engine hot then turn it off, if you suspect head gasket leak or cracked head pull spark plugs so moisture in cylinders can evaporate. let sit till engine is cold then pressure test the system, if it still leaks repeat getting engine hot, if it is sealed drain water and SS and replace with anti-freeze.

Edit: If you have major leaks, or exhaust gasses bubbling in radiator, it most likely won't work.

Back in the late 80's I had a Toyota PU w/ 22RE motor. They were notorious for head gasket failure. When it first started leaking I used "Bars Leak" to try and stop the leak until I had time to get it fixed. Was so long ago I don't recall if it worked or not? It did get to the point that it was overheating and the head gasket was replaced.

The one thing I do remember is how the Bars Leak made some of the rubber components of the cooling system swell. There were a few small hoses that did not carry pressure and weren't clamped, but did carry coolant (ex: radiator overflow to coolant expansion bottle) where the fit was so loose the hoses would not stay attached.

Probably no help, but there is my experience. Since I switched to Ford Rangers in the 1990's I no longer have any vehicle issues.

Well... not exactly true. But my 3 Ford Rangers since (1999, 2001, & my current 2011) have all been less troublesome (and less prone to rust) than that Toyota was.

Cyclotronguy said:

Yeah.......it generally delays the fix, but it's usually a bigger fix later on.

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That was my experience...

I have used this product:

It stays in suspension in the coolant. When you drain the system, the additive drains out also.

Bill

Personally I wouldn't use anything like this except in an emergency, or if I plan on junking the vehicle soon.

Better to just fix it properly. Anything that can stop a leak can also cause clogs in the system.

tdmidget said:

I have had very good results with K&W block seal.

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IIRC the liquid in K&W is sodium silicate, with some brass/copper??? metal flakes.

As for how long any of these last, your mileage may vary. I used sodium silicate in a chevy stepvan that I bought from the USAF, ran it over 100K miles over several years and sold it still running strong. Also used it in a chevy Luv truck that had been converted to an aircraft tug, we called it the Luv Tug. I drove that thing for 3 years on the street, it died when the belt tensioner failed.

rons said:

Do these plug up slow leaks on engine gaskets?

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Want to be more specific? Big difference between a head gasket leak and a water pump gasket leak.

Many years ago I had a small radiator leak and used Prestone Stop Leak. It only made the leak slower. I could look in the radiator cap hole and see the clogged tubes which caused the noticeably higher position of the needle on the engine temp gauge. Pulled the radiator and had a shop open it up and manually clean out all the tubes and fix the leak.

I'll never use a Stop Leak type product again.

crack a few eggs into the radiator. Only if this is the last fix before the vehicle goes to the scrapyard.

Otherwise fix it the right way.