Changing Your Coolant

*MEDIUM*

You should change your coolant at intervals recommended by your owner's manual, or sooner if it gets dirty. This interval is generally every 30,000 miles or 36 months, whichever comes first. Coolant must be replaced at the scheduled time interval even if the vehicle is not driven because the rust prevention and lubrication additives lose their effectiveness with time.

Replace your coolant using the following procedure:

  1. Park the vehicle on level ground in a well-ventilated area with the engine OFF, the parking brake engaged, and the transmission in PARK (for automatic) or REVERSE (for manual). Allow the engine to completely cool down if it has been run recently.
  2. Remove the radiator pressure cap. This will provide an air vent into the radiator and allow the coolant to drain from the radiator. Set the passenger compartment heater control to HOT.
  3. Locate the radiator draincock using your owner's manual. It is usually at the bottom of the radiator near one side. It may have a wing nut or similar attachment. Place a drain pan of sufficient capacity underneath the radiator draincock.
  4. Loosen the draincock in a counterclockwise direction by hand or gently with pliers. Remove the plug and allow your coolant to drain completely into the pan. If the radiator does not have a draincock, it will be necessary to disconnect the lower radiator hose from the bottom of the radiator to permit the coolant to drain.
  5. Replace the radiator draincock and tighten it in a clockwise direction, or reconnect the lower radiator drain hose if applicable.
  6. Remove the coolant recovery reservoir (if present) from any mounting brackets and drain its contents. Reinstall the recovery reservoir and reconnect the recovery hose.
  7. If the used coolant is very dirty or scale is noticed inside the recovery reservoir, a chemical cleaner should be run through system before adding new coolant. Fill cooling system with water, add the cleaner, and run the engine according to instructions provided with the cleaner. Drain the solution from the cooling system after it cools to avoid being burned. Replace the radiator draincock. Even if the used coolant is not very dirty, the cooling system should be filled with pure water and run for a few minutes anyway. This removes used coolant trapped in the engine block and heater core; it also removes rust and scale still in the system. Drain the water through the radiator draincock.
  8. Consult your owner's manual for the recommended type, mix, and quantity of fresh coolant to add to the system. A 50/50 mixture of ethylene glycol-based antifreeze and water is appropriate for most purposes.
  9. Use a funnel to add sufficient pure antifreeze directly to the radiator. For example, in a cooling system with a 10 quart capacity, 5 quarts of antifreeze (10x50%) would be added to the radiator. Determine your cooling system capacity from your owner's manual.
  10. Finish filling the radiator to the top with water. (On engines with no coolant recovery reservoir, finish filling the radiator with water to a level about 2" below the bottom of the filler neck.) Remember that some water (about 2 quarts) is already in the system since it was not drained (e.g., from engine block, heater core, etc.). Thus, the amount of water needed to finish filling the radiator will be less than the amount of antifreeze added to achieve a 50/50 mix. Use distilled water instead if the tap water is "hard" (has high mineral content) or has high alkaline content, otherwise rust or scale might form in the system.
  11. Fill the coolant recovery reservoir (if present) to the COLD or MINIMUM level with the mixture of antifreeze and water.
  12. Start the engine and allow it to warm-up. Keep the radiator cap off until the upper radiator hose becomes warm (that is, the thermostat opens). This allows air bubbles trapped in the system to be released. Then replace the radiator cap and allow the engine to reach operating temperature.
  13. Check for a coolant leak at the radiator draincock and correct if necessary. Check the coolant level in coolant recovery reservoir. It should be at HOT or MAXIMUM. Add more coolant to the recovery reservoir if necessary. Close the hood.
  14. Place used coolant in plastic jugs and dispose of it properly. Take the coolant to a recycling center or service station.

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