Auto Extra ST5516 Heavy-Duty Multi-Purpose Permanent Coolant Leak Repair 16 oz

K-Seal HD ST5516 is a heavy-duty, multi-purpose, one-step permanent coolant leak repair formulated for large-capacity water-cooled engines. The 16 oz bottle is designed to treat cooling systems up to 50 quarts, making it ideal for large trucks, RVs, buses, tractors, and other heavy-duty vehicles.

Key Features:

• Permanently seals leaks in the radiator, head gasket, engine block, cylinder head, heater core, freeze plugs, and water pump casing
• Compatible with all types of antifreeze and coolant — no draining or flushing required before or after use
• Simple one-step application: shake the bottle, pour into the cooling system, and drive as normal
• Works on aluminum and hard plastic cooling system components
• Unique formula seeks out cracks and holes and permanently seals them without negatively impacting engine cooling efficiency
• 16 oz bottle treats cooling systems up to 50 quarts; additional bottles can be used for larger systems

K-Seal HD ST5516 delivers a fast, reliable, and permanent repair for serious coolant leaks in heavy-duty applications — no mechanic or system flush required.