How to Replace Coolant

Old antifreeze rusts and corrodes the coolant system in your vehicle if not changed at recommended intervals. Antifreeze acid content increases with time, clogs radiator and coolant passages and damages water pump and gaskets. Eventually, the engine will suffer form high temperatures, leaks and inadequate functioning of the cooling system. Following these simple steps will help you service the cooling system and keep its components functioning properly for a much longer time.

Things You'll Need

  • Drain pan
  • Rag
  • Make sure the engine is cool, apply the parking brakes and open the hood.

  • Remove the radiator cap and inspect the coolant by rubbing your finger in the antifreeze mixture. Inspect it for the presence of foreign matter, oil and rust. If the presence of contaminants is detected, have the cooling system flushed and cleaned.

  • Check radiator hoses and clamps for possible leaks and repair or replace as needed after draining the antifreeze from the system.

  • Locate the drain valve along the bottom of the radiator.

  • Place a drain pan on the floor underneath the cooling system drain valve, loosen the valve and remove the radiator cap.

  • Wait until the coolant mixture has drained from the system. If your engine block is equipped with a cooling drain plug or bleed screw, place the drain pan underneath the plug and remove it.

  • Remove the drain pan from underneath the car once the coolant has stopped draining from the engine block.

  • Place a garden hose over the radiator neck and run water through the cooling system until you see clear water coming out of the radiator drain valve and engine plug.

  • Let the water drain out of the system and tighten the radiator and engine drain valve and plug.

  • Refill the cooling system with the same amount of new antifreeze and clean water through the radiator neck.

  • Start the engine and let it idle for a few minutes until the thermostat opens. Check the coolant reservoir and make sure to fill it with new coolant mixture--antifreeze and water--up to the “Full Hot” mark. If your vehicle does not have a reservoir container, let the engine cool down, remove the radiator cap and fill the system with new coolant. Make sure the level reaches 1 inch below the bottom of the radiator neck. Check regularly until the proper level is reached.