K-Seal HD is designed for large engines including heavy goods vehicles, tractors, heavy plant and other commercial vehicles. Leak Repair; the simple, permanent solution to cooling system leaks. K-Seal HD fixes most leaks in larger water-cooled engines. It is compatible with all coolant system additives and kinds of antifreeze, meaning you can use K-Seal HD with confidence at all times. With K-Seal HD there's no need to take a commercial vehicle off the road - just apply and run the engine as normal. K-Seal HD's scientifically-tested formula, containing ceramic microfibers and copper particles, will seek out cracks and holes and provide a guaranteed repair for the lifetime of the engine.