K-Seal ST5501 Multi Purpose One Step Permanent Coolant Leak Repair - 1 or 6 Pack

This permanent coolant leak repair formula seals cracks and holes throughout the engine’s cooling system. It’s compatible with all antifreeze types and installs easily with a simple shake-and-pour process—no draining or flushing required.

Specifications & Features

• Application: Radiators, head gaskets, heater cores, freeze plugs, water pump casings, cylinder heads, and engine blocks
• Sealant Composition: Ceramic microfibers and copper particles suspended in a proprietary fluid
• Leak Size Capacity: Repairs holes up to 0.635 mm
• Mixes safely with all types of antifreeze — no chemical incompatibility concerns
• Seals form under system pressure and heat to create a long-lasting bond
• No draining, flushing, or system teardown required before use
• Used by professional technicians and fleet maintenance crews worldwide
• Fixes coolant leaks fast to prevent engine overheating or failure

Compatible Leak Types

• Head gasket leaks where coolant enters the combustion chamber
• Cracked engine blocks or stressed cylinder heads that allow coolant to escape
• Water pump and radiator leaks caused by age, vibration, or thermal cycling