You don’t technically ‘replace’ Prestone Cooling System Flush. It’s a single-use cleaner that helps remove contaminants and limescale from the cooling system when flushing the radiator.

Here’s how to use it:

  1. Drain the old coolant/antifreeze from the cooling system. If you’re not sure how, read our comprehensive guide on how to do a coolant flush.
  2. Replace the radiator drain valve and add Cooling System Flush to the coolant reservoir. Don’t replace the cap.
  3. Start the car and let the engine run for 5-10 minutes. This will circulate the product through the system, where it will lift contaminants and limescale.
  4. Switch off the engine and allow it to cool. Then, repeat the steps you took to drain the soiled cleaning solution from the system.
  5. From there, it’s a case of topping up your car with high-performance coolant/antifreeze.