The coolant in a car should be replaced at least every two years. The radiator and coolant system hoses need to be flushed of all fluids, sediment and corrosives before new coolant is added. Driveway mechanics commonly use a garden hose to flush out radiators. Replace your own coolant and flush the radiator for no more than the cost of supplies.
Stop the car at the site of coolant replacement and allow the engine to cool completely. This may take an hour depending on how long the car has run.
Put on rubber gloves to avoid skin contact with the ethyl glycol in the engine coolant. Raise the hood.
Locate the radiator drain plug near the bottom of the radiator. Place the drip pan under the plug and open the drain by unscrewing the winged plug valve with counterclockwise rotation as far as possible. Coolant will begin to pour into the drip pan.
Remove the cap on the coolant recovery tank. This is the tank where coolant is added. The cap may be labeled "Engine coolant only."
Remove the radiator cap. The cap is usually in the center of the radiator top. The lack of pressure in the cooling system erases the need for caution while unscrewing the cap.
Drain all coolant from the system, replace the caps and tighten the drain valve. Pour the used coolant into containers for recycling.
Fill the system with tap water from a garden hose. Start the car and leave it running until the engine reaches operating temperature. Use the temperature gauge to assess this or wait for the cooling fan to turn on.
Turn off the engine and allow the car to cool again. Place the drip pan under the radiator drain plug. Open the valve and remove the caps from the radiator and coolant recovery tank. Drain all fluid and pour into containers. Close the drain valve and replace the radiator cap.
Pour flush kit fluid into the coolant recovery tank. Add water from the garden hose until the system is full. Run the engine for the duration recommended by the flush kit manufacturer. Allow the car to cool completely.
Place the drip pan below the drain and open the valve. Remove the caps from the radiator and recovery tank. Drain the fluid completely. Remove the drip pan and contain the fluid for recycling.
Close the drain valve and replace the radiator cap. Mix one gallon of new coolant with a gallon of water. Add the mixture to the coolant recovery tank until full. Start the car and run the engine until the level in the recovery tank recedes. Pour more coolant mixture into the tank to top it off. Replace the cap on the recovery tank.
