K-Seal’s advanced formula uses ceramic microfibres together with copper particles of varying size to ensure a fast and permanent seal of most holes or cracks in the cooling system, up to 0.75mm. The special chemical formulation can flow into cracks so fine that they cannot even be seen with the naked eye to form a superstrength seal. The crack or hole is actually filled from top to bottom with the K-Seal formula resulting in a complete ‘weld’ and permanent repair. The copper in the K-Seal formulation not only contributes to the strength of the repair but it also helps to conduct heat across the crack or hole. This eliminates hot spots that would normally form with a non-metallic repair. K-Seal can be left in the cooling system and will continue to repair leaks as they happen. You won’t even notice that there was a problem. In fact, K-Seal is ideal to use when rebuilding engines. Often there can be micro-cracks which would go unnoticed after the repair has been completed. Adding K-Seal to the cooling system immediately after a repair and also after each coolant replacement ensures that any and all leaks are sealed thus preventing time consuming and costly returns. K-Seal is specially formulated to permanently seal cracks in the engine block and head. This unique product is guaranteed to mix with all types of glycol based coolant and antifreeze. K-Seal can also be used to seal holes and cracks in the head gasket, radiator, heater core, freeze plugs, water pump casing and other metal components of the cooling system in both petrol and diesel engines. K-Seal will not seal water to oil leaks or oil to water leaks. It must leak to an atmosphere to be able to work properly.