K-Seal Heavy Duty ST5516 Coolant Stop Leak 16oz for Large Trucks, RVs, and Tractors

K-Seal HD Stop Leak is a one-step, coolant leak repair designed for heavy-duty, water-cooled vehicles. K-Seal HD Stop Leak 16oz is suitable for large cooling systems with capacities greater than 20 quarts, making it ideal for trucks, RVs, tractors, and other heavy-duty equipment. K-Seal HD repairs coolant leaks in radiators, hoses, heater cores, engine blocks, and blown head gaskets without the need for draining or flushing the system. This heavy-duty coolant stop leak is simple to use—just shake, pour, and go. K-Seal HD Stop Leak 16oz is compatible with all standard antifreeze and coolant types and is engineered to provide a reliable, long-lasting repair for demanding applications.

• • One-step coolant leak repair for heavy-duty vehicles • No draining or flushing required—simply shake, pour, and go • Designed for large cooling systems with capacities greater than 20 quarts • Repairs leaks in radiators, hoses, heater cores, engine blocks • Compatible with all standard antifreeze and coolant types • Ideal for trucks, RVs, tractors, and other heavy-duty equipment • 16oz bottle formulated for demanding, high-capacity cooling systems
• • Provides a durable, long-lasting repair for coolant leaks under heavy-duty operating conditions • Helps seal leaks caused by cracks, and porosity • Works while the engine is running with no need for system disassembly • Safe for use with metal, plastic, rubber, and composite cooling system components • Does not clog radiators or heater cores when used as directed • Suitable for commercial, fleet, and recreational vehicle applications • Trusted solution for high-mileage and hard-working engines
• • Repairs coolant leaks caused by cracks, pinholes, and porosity throughout the cooling system • Seals leaks in radiators, hoses, and heater cores • Engineered to circulate and seal leaks while the engine is running • Designed for heavy-duty applications and high-capacity cooling systems • Safe for use with metal, plastic, rubber, and composite cooling system components
• • Begins sealing coolant leaks quickly as the product circulates through the cooling system • Delivers fast-acting performance without requiring extended downtime • Provides effective leak repair during normal engine operation • Helps reduce vehicle downtime for heavy-duty and commercial applications
• • Formulated for large, heavy-duty cooling systems up to 50 quarts • Ideal for large trucks, agricultural equipment, and commercial vehicles • Scalable dosing allows use in even larger cooling systems when needed • Designed for high-capacity, high-demand applications
• • Safe for use on aluminum, plastic, rubber, and composite cooling system components • Compatible with modern radiator and cooling system materials • Designed to seal leaks without damaging sensitive cooling system parts
• •#1 Brand for coolant stop leak solutions for automotive and heavy-duty applications • Proven formulation relied on by professionals and DIY users • Designed to deliver dependable performance in demanding cooling systems
• • 16 fl oz bottle formulated for very large and high-capacity cooling systems • Provides sufficient coverage for heavy-duty trucks and equipment • Sized specifically for demanding, large-vehicle applications