Primary Use

Cooling System Stop Leak will plug the pinholes in the radiator and heater core without clogging the cooling system passages.

Key Features

  • OEM-Approved service chemical.
  • A radiator re-core may be avoided.

Directions for Use

  • Shake well before using.  
  • Add contents directly to radiator coolant.
  • Do not pour into overflow tank.  
  • Top up radiator if coolant level is low.
  • Start engine and allow coolant to circulate with radiator stop until leak stops.  
  • Do NOT flush radiator.
  • If leak persists, see service technician.


1. Does temperature effect this products performance?

No, it is not temperature sensitive.

2. What substance plugs the pinholes?

An organic powder contained within the additive.

3. What causes cooling system leaks?

Stone chips, corrosion over time, wear and tear.

4. How long is stop leak effective for?

As long as the radiator fluid is in the radiator, it will keep recirculating.

5. Is it compatible with all coolants?


Why Shrader?

  • Canadian-owned and operated, Shrader is a complete service company with 60 years of success.
  • A complete one-stop operation. All design, formulation, manufacturing, and supply chain services are managed in-house.
  • Supported with technical expertise in R&D, Manufacturing, Logistics, Sales and Marketing Services.
  • Flexibility and choice in scope and range of services to meet the requirements of our customers.
  • Certified and audited to World Class Standards, with an exceptional record of regulatory compliance and high quality products and service.
  • Provide OEM approved and custom formulation and manufacturing.
  • In-house capabilities and expertise for full range of R&D, Physical and Chemical, Functional and Quality Testing requirements – including Practical End Use Testing Protocols.
  • Partner with clients to design and conduct End Use efficacy testing procedures.


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