Bar’s Leaks Radiator Stop Leak Original is a classic, heavy-duty cooling system sealant formulated with natural particles and active buffing agents to stop micro-leaks and protect internal cooling components.

It is suitable for:

• sealing internal and external cooling leaks, pinholes, and cracks up to 0.9 mm in size;
• sealing minor weeping around head gaskets, engine blocks, heater cores, water pumps, and freeze plugs;
• all petrol, diesel, and gas engines in passenger cars, commercial vehicles, and heavy machinery;
• all radiator materials (aluminium, copper, plastic, and alloys) and all types/colors of antifreeze or water;
• quieting noisy water pumps while protecting against rust, cavitation, and scale formation.

The additive contains fine Rhizex particles and sealing agents that flow naturally through the cooling system without causing blockages. When reaching a leak point exposed to air and pressure drop, the particles accumulate and expand (up to 15%), forming a durable, heat-resistant seal capable of holding system operating pressures. One 150 g container treats standard 4-to-6 cylinder cooling systems up to 12 liters capacity (use 2 containers for 8-cylinder engines or larger systems); simply pour directly into a clean, warm radiator or upper hose and idle/drive the vehicle