Engine Coolant Replacement

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

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

Fig 2: Removing Rear Heater 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

Fig 3: Antifreeze Solution Mixture Percentage Chart
Courtesy of MAZDA MOTORS CORP.
Fill the coolant into the reservoir up to the FULL mark on the coolant reservoir.
Tighten the cooling system cap.
CAUTION:
- If the coolant temperature becomes too high, stop the engine to prevent it from overheating.
Start the engine and let it idle until the cooling fan operates.
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.
Stop the engine and wait until it is cool.
Inspect the coolant level. If it is low, repeat Steps 7-12.
Verify there is no coolant leakage.