DIY: How to Perform a Radiator Flush

Before you start your radiator flush, make sure you have everything you need. There’s nothing worse than draining your radiator only to realize that you need to drive to the auto store for something! What you’ll need to perform a radiator flush: Phillips head screwdriver or wrench (whichever your radiator drain requires),Cloth rag, Radiator, Flush […]

Before you start your radiator flush, make sure you have everything you need. There’s nothing worse than draining your radiator only to realize that you need to drive to the auto store for something!

What you’ll need to perform a radiator flush: Phillips head screwdriver or wrench (whichever your radiator drain requires),Cloth rag, Radiator, Flush solution, Coolant, Funnel, Used coolant receptacle, Be sure to let your engine cool completely before you loosen or remove the radiator cap. Hot coolant can be painful!

The first step in your radiator and cooling system flush is to drain the old coolant from the radiator.

Using your owner’s manual or your eyeballs, locate your radiator’s drain plug. It could be anywhere along the bottom of the radiator, and will be either a screw plug, bolt plug or a petcock (simple drain valve). Be sure you have your used coolant receptacle in place under the drain before you open it up.

With your coolant catcher underneath the drain, unscrew it and let the coolant empty completely. If you have a screw or bolt type radiator drain plug, remove it completely. If your radiator has a petcock, open it all the way.

Once all of the coolant have drained from the radiator, replace the drain plug and remove the radiator cap. Add the contents of the radiator flush solution to the radiator. Then fill it to the top with water.

Replace and tighten the radiator cap. Now start the car and let it run until it gets to its operating temperature (the place on the temp gauge that it normally stays at).

Turn your heater on and move the temperature control to the hottest position. Let the car run for 10 minutes with the heater on.

Turn the car off and wait for the engine to cool off. If the radiator cap or metal radiator is hot to the touch, it’s still too hot to open.

Once the engine has cooled down, open the drain and completely empty the contents of the radiator. Your radiator flush is almost finished!

Depending on the size of your coolant receptacle and cooling system, you might have to empty it into a separate container to make room for the second draining. No matter what, never pour coolant on the ground!

Now that you have performed a radiator and cooling system flush, all you need to do is refill the radiator with fresh coolant.

Replace the radiator drain plug or fully close the petcock.

Using a funnel to eliminate spills, fill the radiator with a 50/50 mixture of coolant and water. With the radiator filled, go ahead and fill the plastic coolant reservoir if your car has separate openings, again with a 50/50 mix.

Tighten all of your caps well.

It’s a good idea to check your radiator coolant level in a day or so to be sure it’s proper, sometimes an air bubble works its way out and you need to add a little.