Permanently repair and seal leaks in head gaskets, cylinder heads, freeze plugs, heater cores, and even engine blocks! The advanced formula quickly gets to work sealing leaks in both steel and aluminium parts throughout your engine system Nitrox steel weld works with ALL types of anti-freeze in the coolant system, saving you from flushing your system. Not only that, Nitrox Steel Weld stays active in your coolant system, ready to plug any future leaks or cracks and the anti-rust formula helps prevent long-term damage and wear to your radiator.