Engine Coolant Replacement

2008 Mazda 6 s Sport, 4D Hatchback, StandardSECTION Engine Coolant Replacement
WARNING: This page is about a different car, the 2005 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.
WARNING:
  • Drain the engine coolant when the engine is cold, otherwise it may burn you and cause serious injury.
  1. Remove the cooling system cap and the radiator drain plug.
    Fig 1: Identifying Cooling System Cap And Radiator Drain Plug
    G03643828Courtesy of MAZDA MOTORS CORP.
  2. Drain the engine coolant into a container.
  3. Flush the cooling system with water until all traces of color are gone.
  4. Let the system drain completely.
  5. Tighten the radiator drain plug.
    CAUTION:
    • The engine has aluminum parts that can be damaged by alcohol or methanol antifreeze. Do not use alcohol or methanol in the cooling system. Use only ethylene-glycol-based engine coolant.
    • Use only soft (demineralized) water in the engine coolant mixture. Water that contains minerals will reduce the engine coolant's effectiveness.
    • Engine coolant damages paint. If engine coolant does get on a painted surface, rinse it off quickly.
  6. Referring to the following chart, select proper volume percentage of the water and engine coolant.
    ANTIFREEZE SOLUTION MIXTURE PERCENTAGE

    Engine coolant protection Volume percentage (%) Gravity at 20 °C {68 °F}
    Water Coolant
    Above -16 °C {3 °F} 65 35 1.057
    Above -26 °C {-15 °F} 55 45 1.072
    Above -40 °C {-40 °F} 45 55 1.086
  7. Slowly pour the engine coolant into the radiator up to the engine coolant filler port. (L3 engine model)
  8. Fill the engine coolant into the engine coolant reserve tank up to the F mark on the engine coolant reserve tank.
  9. Tighten the cooling system cap.
    CAUTION:
    • If the engine coolant temperature becomes too high, stop the engine to prevent it from overheating.
  10. Start the engine and idle it until the cooling fan operates.
  11. After engine warms up, perform the following steps.
    1. Run the engine at 2,500 rpm  for 5 min. 
    2. Run the engine at 3,000 rpm  for 5 s,  then idle.
    3. Repeat steps (2) several times.
    4. Idle the engine for 1 min. 
  12. Stop the engine and wait until it is cool.
  13. Inspect the engine coolant level.
    • If it is low, repeat Steps 7-13 (L3 engine model), Steps 8-13 (AJ engine model).
  14. Install the cooling system cap.
  15. Inspect for engine coolant leakage. (See ENGINE COOLANT LEAKAGE INSPECTION  .)
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.