Similar to an oil change, a coolant flush gets rid of the sludgy buildup so your coolant can circle through the system and keep your engine parts cool and lubricated. You should do a coolant flush once every couple of years.
To do a coolant flush, let the car cool for at least two hours and then jack up the front end. Next, find the radiator under the hood and clean the fins on the front and back with soapy water and a brush.
Inspect the radiator for damage, leaks, and rust before you do the flush. Get back under the car and find the radiator drainage valve, and then place a pan there to catch the fluid. Take out the plug in the valve and let the coolant drain. Remember, it’s toxic!
Put the plug back and fill the radiator with water from a hose, then let your car run for ten minutes to loosen the rest of the coolant. Unplug it again, let the water drain out into a pan, and repeat the process a couple more times. Finally, plug everything back up, add the new coolant, and you’re done!