ALUMASEAL Radiator & Heater Core Leak Sealant Radiator Stop Leak is specially formulated to seal leaks in radiator and heater cores. Seals without clogging cooling system passages. Safe on all metal, plastic and rubber parts. Compatible with all coolants and antifreeze in all liquid cooled engines. Permanent seal within minutes. 20 gram powder tube or 473ml bottle treats 21 litre system capacity. Bottle 473 ml contains rust and corrosion inhibitor and seal conditioner to lubricate water pump seal.