I am posting this as it seems many people seem to have a low opinion of products such barsleak or rad weld along with many others, branded or otherwise.
What I wanted to understand ( i don't have a leak by the way! Just building my knowledge) is how they actually work. They are formulated differently it appears and only solidify with contact with air.
I have seen a number of of posts about don't use barsleak, radweld, stopleak etc but there seems to be two differing types pellets and liquid.
I could see where pellets would not dissolve if the vehicle was not run at a temp and potentially cause a problem, but a liquid as long as it was not exposed to air unsure how it could coat a radiator inner for example?
If a car was sitting for long periods I could understand settling of fibres but again if not in contact with air how would it solidify? Surely it would just circulate again?
Again Alui powders, pepper, oats eggs and just about anything else you could chuck in have a similar principal. But my question is if the stopleak are designed to solidify on contact with air how can then coat block your radiator?
I have used different product on occasions over the years and agree completely that there is nothing like a proper repair.
These products work by plugging the leak. In that process, they are also quite effective at plugging the radiator. They also plug up the engine cooling passages.
You said it - there is no substitute for a proper repair.
We used to use a product called water glass.
I'm not sure they work by exposure to air or by simply "clotting" to fill leaks like a wound to the skin. In any case, the cooling system of the Model T is NOT pressurized or closed. It's open to air all the time.
The ones that use sodium silicate (liquid glass) as a carrier will harden with exposure to carbon dioxide. The more CO2, the faster it hardens. Some foundry core molds are made this way. It only takes seconds for it harden.
Imagine your radiator tank full of sodium silicate and some filler clotting then these clots making their way down the cooling channels. The smaller clots may make their way through the system. Larger ones may not.
I almost ruined an engine using sodium silicate, it plugged the whole radiator, never again for me. Do a proper repair.
As I said not somthing I need just interested in the theory behind it and how they work rather than they work.
A proper repair is of course most appropriate but why I don't understand is why some people seem to have luck with these and some don't, maybe if you adding it to a system that's already built up a layer of crud then there's less room and therefor blocks quicker rather than a fresh system
Maybe it's a difference between areas with hard water or soft water - I have soft water in my area and haven't had any problem with various kinds of radiator seal products I've had to use over the years - just that it can't make wonders, only seal thin glitches. It can't seal wide gaps that moves - in that case soldering or replacement is the only way.
I agree that stop leaks are a temporary fix, but sometimes it is the "fix of choice". Not the "proper" fix, but what we are going to do today .... because I have to. Here is a link to a fix I had awhile back when hauling a bunch of T parts home. The fix worked as a "clotting" fix as Ken stated.
It's interesting, how opinions differ and divide.
The pepper solution I have seen in another car worked well for a few hits of driving a number of years ago.
I was just intrigued at how a 'clotting solution' would clog up a system, but then on reading more maybe people have added so many different solutions and keep adding and keep adding this is the problem for the failure rather than the substance itself.
Anyway it is what it is whether you use a egg, pepper or stop leak it's a temp solution/ get me home!
coarse ground black pepper was kept in my old jeep cj for years ,and was added regularly .if you like pepper it smelled great !. egg white was tried by me after a real old timer told me about it . he insisted it would work ,I did ,and it did hold up for years in a modern pressurized car . the same old timer fixed another radiator leak squirting like a fountain using wood putty ! witch held up until i had it rebuilt years later
There is nothing more permanent than a temporary solution that works
A porous block on my Cummins diesel engine was repaired with Barr's StopLeak. That was back in the mid 90's. Truck is still going strong with a paltry 400,000 kms on it and it doesn't leak, drip or loose coolant. Since that was our only vehicle at the time, it would have been a huge hassle for us to leave the truck at the dealer for them to search and find the leak in the block.
I've said this many times here but if you use any leak stopper product and then just go for a drive around the block a few times - it's gonna plug up tubes. When I did my repair I poured the StopLeak in as I was heading on a long road trip. My first stop was probably for fuel 10 hours later. There was ample time for the pellets to dissolve and work their magic.