How to Power Flush Your Cooling System

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Auto cooling systems should be flushed out once every year if you live in a moderate climate and twice a year if you live in a harsh climate.

Professionals use extremely expensive machines to perform a power flush on cars cooling system. The shade tree mechanic can do a reasonable job with a "Flush and Fill Kit" made by Prestone and an ordinary garden hose. Many people simply open the petcocks and drain the old coolant from their cars cooling system and then refills with fresh coolant. I suppose that is better than not replacing the coolant at all but not many betters. Power flushing the system not only removes every drop of the old coolant from the system but forces out the majority of rust and scale build up too. There are other power flush adapters similar to the Prestone "Flush and Fill Kit" that are permanently installed on a vehicle, that work equally well, but Prestone is my favorite.

Things that you will need

Prestone "Flush and Fill" kit or a similar kit

Basic mechanic's hand tools

Two lengths of garden hose

How to install the Flush and Fill kit

  1. Allow the engine ample time to cool down. Loosen the radiator cap to release any residual system pressure, and then retighten the cap.
  2. Locate the two heater hoses extending from the engine compartments firewall to the engine. One hose extends from the firewall to the water pump. The other hose, the heater inlet hose, extends from the firewall to the top of the engine. Cut the heater inlet hose and permanently install the "Flushing TEE."

How to perform the flush

  1. Remove the radiator pressure cap and the "Flushing Tee's" cap. Install the Prestone Back-Flow preventer on the Flushing TEE. Attach the Black end of the Back-Flow preventer on the flushing tee. Attach the garden hose to the yellow end of the back-flow preventer.
  2. Snap the Prestone "Splash Tube" into the radiator's filler neck and direct it away from the cars body.
  3. Turn on the water and check to see that water/coolant is running from the "Deflector Tube" or radiator hose fitting. If you have a car with a sealed cooling system, a system with no radiator cap, you will have to remove a radiator hose.
  4. Continue the flush until the water runs clean.

Filling the system with new coolant

  1. With the cap off the flushing tee, pour the required amount of coolant into the radiator, expansion tank, or thermostat housing on a sealed system. When a small amount of coolant emerges from the flushing tee, cap off the tee and replace the radiator cap.
  2. Run engine for 10 to 15 minutes. Shut engine down and allow cooling down completely.
  3. Add more coolant to fill the system to fill the system completely and then replace cap tightly.


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