Penrite Radiator Stop Leak 375ML

In stock
Regular price $14.00 inc. GST

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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

  • Purple OEM Coolant Anti-Freeze Anti-Boil (OEM Approved)
  • Red OEM Coolant Anti-Freeze Anti-Boil (OEM Approved)
  • Green OEM Coolant Anti-Freeze Anti-Boil (OEM Approved)
  • Blue OEM Coolant Anti-Freeze Anti-Boil (OEM Approved)
  • 350,000KM Green Anti-Freeze Anti-Boil
  • HD EC-01 Anti-Freeze Anti-Boil
  • 10 Tenths Power Sports Coolant Anti-Freeze Anti-Boil
  • PGXL Coolant Anti-Freeze Anti-Boil
  • Universal Top Up Premix Anti-Freeze Anti-Boil

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.


  • Stops coolant leaks
  • Safe for rubber hoses and all metals, including aluminium
  • Compatible with anti-freeze/anti-boil solutions
  • One bottle treats up to 12 litres