Zerex Super Sealer is an all-natural sealant for cooling systems and the only product on the market tested and approved by Cummins. Seals leaks permanently in about an hour. Water based formula flows through the smallest of passages with no clogging. Proven safe in multiple applications and can be used to prevent leaks in the future.

Patented and Breakthrough Technology!
• A carefully selected formulation of cellulose fibers and bentonite particles quickly cover cracks, and cure to form a permanent seal. The
  seal has been proven to be quick and effective in various internal and external leaks commonly encountered in engine blocks, heads,
  radiators, EGR coolers, and gaskets.
• Carefully formulated to avoid obstruction of narrowest coolant passages (e.g. heater cores, DEF heater valves, etc.)
• No harm to coolant or cooling system (all-natural, non-metallic, inert ingredients) Cellulose fibers are soft, non-abrasive. No active
  chemicals as in competitive coolant sealant systems.
• Super Sealer is a proven technology in both light duty and heavy duty applications.
• As demonstrated in the field and on the ASTM 3147 test rig.
• Super Sealer permanently seals existing leaks, and can be used repeatedly if new leaks form later.
• Seals leaks in under an hour