Engine Coolant Replacement

WARNING: This page is about a different car, the 2005 Mazda MPV. However, it is still accessible from the selected car via links, so may be relevant.

Remove the cooling system cap, the radiator drain plug and the rear heater unit drain plug (if equipped).

Fig 1: Removing Cooling System Cap And Drain Plug
Courtesy of MAZDA MOTORS CORP.

Fig 2: Locating Rear Heater Unit Drain Plug
Courtesy of MAZDA MOTORS CORP.
Drain the coolant into a container.
Flush the cooling system with water until all traces of color are gone.
Let the system drain completely.
Tighten the radiator drain plug and the rear heater unit drain plug (if equipped).
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 coolant.
- Use only soft (demineralized) water in the coolant mixture. Water that contains minerals will cut down on the coolant's effectiveness.
- Engine coolant will damage paint. If engine coolant does get on a painted surface, rinse it off quickly.

Referring to the following chart, select proper volume percentage of the water and coolant.

ANTIFREEZE SOLUTION MIXTURE PERCENTAGE

Coolant protection	Volume percentage (%)		Gravity at 20 °C {68 °F}
Coolant protection	Water	Coolant	Gravity at 20 °C {68 °F}
Above-16°C{3°F}	65	35	1.057
Above-260C{-15°F}	55	45	1.072
Above-40 °C {-40 °F}	45	55	1.086

Perform the following procedure for vehicles without a rear heater.
1. Fill the coolant into the reservoir up to the FULL mark on the coolant reservoir.
2. Tighten the cooling system cap.
  CAUTION:
  - If the coolant temperature becomes too high, stop the engine to prevent it from overheating.
3. Start the engine and let it idle until the cooling fan operates.
4. After engine warms up, perform the following steps.
  1. Run the engine at 4,000 rpm for 1 min .
  2. Run the engine at idle for 1 min .
  3. Repeat steps 1) and 2) several times.
  4. Turn on the main and rear heaters and verify heat from heater vents.
5. Stop the engine and wait until it is cool.
6. Inspect the coolant level. If it is low, repeat Steps ( 1)-(6).
7. Verify there is no coolant leakage.
Perform the following procedure for vehicles with a rear heater.
NOTE:
- Engine coolant flows to both the front and rear heaters when the water shutter valve is open.
- The passage to the front heater is blocked when the water shutter valve is closed so that engine coolant only flows to the rear heater.
- Verify that the water shutter valve is open after completing the procedure.
1. Verify that the water shutter valve is open.
2. Fill the coolant into the reservoir up to the FULL mark on the coolant reservoir.
3. Tighten the cooling system cap.
  CAUTION:
  - If the coolant temperature becomes too high, stop the engine to prevent it from overheating.
  Fig 3: Opening Water Shutter Valve
  Courtesy of MAZDA MOTORS CORP.
4. Close the water shutter valve.
5. Warm up the engine.
6. After engine warms up, perform the following steps.
  1. Run the engine at 5,000 rpm for 10 sec .
  2. Run the engine at idle.
  3. Repeat steps 1) and 2) several times.
    
    Fig 4: Closing Water Shutter Valve
    Courtesy of MAZDA MOTORS CORP.
    CAUTION:
    If the engine coolant in the coolant reserve tank approaches the low mark, stop the engine, allow it to cool, and then replenish the engine coolant.
7. Turn on the rear heater and verify heat from heater vents.
8. Open the water shutter valve.
9. Turn on the front heater and verify heat from heater vents.
10. Stop the engine and wait until it is cool.
11. Inspect the coolant level. If it is low, repeat Steps ( 1)-(11).
12. Verify there is no coolant leakage.
Fig 5: Opening Water Shutter Valve
Courtesy of MAZDA MOTORS CORP.