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