Penrite Radiator Stop Leak 375mL

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  • Regular price $13.95
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Radiator Stop leak is a high quality water based sealant designed for temporarily fixing leaking cooling systems. Its fast acting formulation effectively seals radiators, heater cores, weeping head gaskets, hose joints and welsh plugs in automotive engines preventing major damage from loss of Coolant and engine overheating.


Radiator Stop Leak is suitable for all types of motorcycles, passenger cars, 4WDs, light and Heavy Duty commercial vehicles, construction, mining ,agricultural and Stationary engines.

Radiator Stop Leak is suitable for use with all types of materials including aluminium, Cast Iron, Copper, Brass, plastics & rubber hoses. One x 375 ml bottle will treat between 6 & 12 litres.

Radiator Stop Leak will not block cooling system passages and is Compatible with anti-freeze anti-boil solutions. If cooling system has lost fluid prior to Radiator Stop Leak being used , we recommend refilling with a quality Penrite Anti-Freeze Anti-Boil coolant such as

  • 8 Year Red Anti-Freeze Anti-Boil (OEM Approved)
  • 7 Year Green Anti-Freeze Anti-Boil (OEM Approved)
  • 7 Year Blue Anti-Freeze Anti-Boil (OEM Approved)
  • 350,000KM Green Anti-Freeze Anti-Boil
  • HD EC-01 Anti-Freeze Anti-Boil
  • PGXL Coolant
  • Universal top up premix

Instructions for Use:

  • Remove radiator cap
  • Shake bottle well prior to using.
  • Start engine and run, with heater on, for 2 minutes
  • Add contents directly to the radiator.
  • Refill radiator and refit radiator cap
  • Leave engine and heater on for 5 minutes.
  • Please Dispose of bottle thoughtfully.


Penrite Radiator Stop Leak is designed as a temporary repair and does not replace the need for mechanical repairs. If leaks are still evident after use, replacement or repair of faulty parts may be required.