Permanently fixes blown Head gaskets, cracked heads and porous engine block. One bottle is enough to Fix gaskets in cars, SUVs and small trucks; large engines Require two bottles. The ceramic micro-fibres in K-Seal Ultimate are carefully produced so that they will seal leaks up to 0.635mm in size. These micro-fibres will naturally migrate to the pressure differential caused by the coolant Leak or failure point. The leak is repaired and the ceramic ingredient Cures to make a long lasting repair.