Forte Radiator Stop Leak should be considered an emergency repair product rather than a permanent cure to a coolant leak. The natural fibres form a stable and long lasting plug (as opposed to biodegradable products using vegetable matter fibres - sugar beet being one such material)

Forte Radiator Stop Leak will not block heater matrixes or radiator cores.

When used as a preventative treatment, Radiator Stop Leak will lubricate the water pump, impeller shaft.