MANNOL 9966 Cooling System Leak Stop 225 ml

Cooling System Sealant is a professional additive designed for the cooling systems of internal combustion engines (ICE) and interior heating systems.
Suitable for any liquid-cooled engine with radiators made of aluminum, copper, plastic, or composite materials.
It is a carefully balanced blend of metal polymers and fine sealing fibers formulated to eliminate leaks and protect the system from future failures.

Product Properties:

• Compatible with all types of coolants and water.

• Effectively seals leaks in gaskets, clamps, small radiator cracks, cylinder head gaskets, water pumps, and cylinder blocks.

• Cures only at leak points, without clogging radiator tubes. Once hardened, it resists vibration, temperature changes, and washing out.

• Ideal for microcracks and hard-to-detect leaks that cause gradual coolant loss.

• Neutral to all materials — metals, alloys, plastics, and rubber.

• Restores the elasticity of seals and gaskets, preventing drying, hardening, and cracking.

• Provides strong anti-corrosion protection and neutralizes acidic residues.

• Extends the service life of the water pump and entire cooling system.

• Can also be used preventively to slow seal aging and prevent coolant leaks.

Application Instructions:

1. Start the engine and let it warm up to operating temperature.

2. Turn on the interior heater.

3. Shake the bottle thoroughly and pour the sealant into the expansion tank (or radiator).

4. One 250 ml bottle is enough for a 10 L system; 325 ml for a 12 L system.

5. Let the engine idle for about 10 minutes.

6. If leaks persist after 3 days, mechanical repair may be required.

Safe, effective, and easy to use — this cooling system sealant provides long-term protection, sealing, and reliability for all engine types.