Wynns Cylinder Block Seal (72250)

• For all water-cooled engines
• Internal and external cracks in cylinder heads, engine blocks and head gaskets, which lead to external or internal water loss to the oil system or combustion chamber.
• In case of severe white exhaust smoke.
• In case of mayonnaise like oil/water emulsion in the oil system (can often be seen on filler cap).
• One bottle treats up to 7 litres of coolant. For larger cooling systems use multiple bottles.
• Not recommended to be used with coolant in the system, first drain the cooling system and refill with clean water.
• DO NOT add to engine oil.
• For radiator leaks use Wynn’s Cooling System Stop Leak

• Repairs cracks in cylinder heads and engine blocks of cast iron and aluminium alloys.
• Solves porosity problems in engine blocks.
• Stops leaks in head gaskets.
• Stops leaks in water pumps
• Assures a permanent repair in 30 minutes.
• Resists high pressures and vibration.
• Does not clog cooling systems.
• Does not repair rubber gaskets.

• Standard Application 

1. For best results first flush the cooling system with Wynn’s Cooling System Flush.
2. Drain cooling system and refill with fresh water.
3. Remove the upper radiator hose and the thermostat.
4. Shake the bottle well before use.
5. In cold temperatures, warm the bottle before application.
6. Pour the contents of the bottle into the opening of the removed thermostat.
7. Replace the thermostat and hose.
8. Top up cooling system with water if required.
9. Start the engine and run up to operating temperature.
10. Fast idle (1500 – 2000 RPM) the engine for a minimum of 15 minutes.
11. Monitor engine temperature during treatment to avoid overheating.
12. Stop the engine and allow to cool completely.
13. Drain the cooling system and flush with clean water.
14. Refill the cooling system with fresh coolant.

• Specialist Application - Cracks in cylinder wall 

Proceed in the same way as above but remove the spark plug (petrol) or injector (diesel) from the damaged cylinder. When several cylinders are damaged, remove the spark plugs (injectors) sequentially, leaving each one out for 5 minutes. 

• Specialist Application - For large cracks 

Proceed in the same way, but leave Wynn’s Cylinder Block Seal in the cooling system for 3 to 4 days, before draining.

• Proceed in the same way as above but leave Wynn’s Cylinder Block Seal in the cooling system for 3 to 4 days, before draining.
• Large visible cracks or holes can be plugged with steel wool prior to application. 

• H314 - Causes severe skin burns and eye damage.
• P280 - Wear protective gloves, eye protection.
• P301+P330+P331 - IF SWALLOWED: rinse mouth. Do NOT induce vomiting.
• P303+P361+P353 - IF ON SKIN (or hair): Take off immediately all contaminated clothing. Rinse skin with water/shower.
• P305+P351+P338 - IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.