Permanently seals small leaks anywhere in the cooling system. Seals leaks in radiators, hose pipes and water pumps. Can even SEAL HAIRLINE CRACKS IN ENGINE BLOCK. Guaranteed; Will NOT clog the system due to a revolutionary new formula. Is compatible with all types of water based coolants. Is not affected by Anti-Freeze and will continue to seal the leak. Miracle Seal: Can be used to prevent leaks Contains lubrication additives Contains anti-corrosion additives C-Tec Miracle Seal 250ml Leak Sealer