Penrite Block and Cylinder Head Seal 250ml

In stock
Regular price $14.90 inc. GST

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Block & Cylinder Head Seal is a permanent engine block, cylinder head and cooling system sealer formulated with ceramic fibres and copper to ensure a fast and permanent seal of gaskets, fractures and cracks in a vehicle’s cooling system.


Block & Cylinder Head Seal is designed for use in all modern automotive cooling systems and is compatible with all types of materials used throughout the cooling system, including all metals, plastics and rubber components. It is compatible with all types of coolants and will not block the cooling system.

Block & Cylinder Head Seal uses the latest ceramic fibre technology combined with copper to permanently seal broken and weeping head gaskets, block and cylinder head fractures, radiator cracks or splits and engine welch plugs to prevent coolant loss and engine overheating. It will also seal broken heater cores and prevent expensive coolant leakage that can cause damage to the inside of a vehicle.


One bottle will treat up to 19 litres of coolant.

  • Allow engine to cool (make sure engine is cool enough to remove the radiator cap)
  • If the coolant is rusty or dirty, flush out and refill the cooling system with the correct Penrite coolant*
  • Shake bottle well and pour the contents of the Block & Cylinder Head Seal into the radiator or radiator overflow tank
  • For very small capacity 4 cylinder and fewer engines, use half the contents of the bottle
  • Fill radiator or overflow tank to the proper level with coolant*
  • Turn the heater on full and the fan on high
  • Start vehicle and idle the engine for at least 15 minutes
  • Turn the vehicle off and allow it to cool
  • Top up the radiator or overflow tank with a coolant*
  • Check that leaks have been sealed. If leaks are still present, a mechanical repair may be necessary
  • Vehicle may be driven normally following these procedures

Please Note

Product may change Colour over time, depending on the frequency of exposure to air. This will not affect the performance of the product. Ensure bottle cap is tightened after use. The remaining product should be used within 12 months.


  • Latest ceramic fibre and copper technology
  • Seals leaks in one application
  • Fixes expensive cylinder head and gasket repairs
  • Very economical compared with mechanical repairs
  • Compatible with all coolants, metals, plastic and rubber


Sizes: 250ml

Dimensions: 18x5x5 cm

Colour: Bronze