The secret behind how K-Seal can repair a coolant leak is down to its contents of a specially developed blend of chemical ingredients including ceramic microfibres and copper particles. When adding to the cooling system the ingredients disperse and flow freely around the system suspended in the coolant. If coolant is leaking from the system, either externally (look for a puddle under the engine) or internally across the head to the cylinders, then K-Seal will follow the coolant through the hole or crack and try to fix the coolant leak.
Stop coolant leak
The first thing that happens is that the microfibres begin to mesh together within the crack or the hole building a seal literally fibre by fibre. In reality this happens almost instantly once K-Seal has reached the leak.
IMPORTANT: The particles in K-Seal are very precisely designed to be large enough to repair holes up to 0.7mm in size but deliberately small enough to never block any passageways or tubes within the cooling system, including the heater core and radiator.
Once the microfibres have sealed, and fixed, the leak a combination of exposure to an atmosphere, either the external atmosphere or the gases within the combustion chamber, together with the heat within the cooling system and engine causes the K-Seal formula to cure. This results in an extremely strong and permanent seal able to withstand even the high pressures from the combustion chamber.
This is how K-Seal is able to repair head gasket failures, even where the cooling system is being over pressurised by exhaust gases entering the system.