Level check
The fluid level in the reservoir on a cold engine should be near the FULL mark on the reservoir. Add fluid only to the tank. The radiator cap is only loosened to replace the fluid and flush the cooling system.
Coolant replacement
1. With the engine running, move the heater thermostat to the WARM position.
2. Remove the tank and drain the liquid from it.
3. Place a drip tray under the radiator and open the valve by turning counterclockwise.
4. Remove the radiator cap by slowly turning counterclockwise and pressing.
5. Drain the liquid, close the radiator valve.
6. Fully open the heater valve.
7. On 4-cylinder Odysseys, unscrew the vent fitting on the thermostat.
8. Install the reservoir and fill with fresh coolant up to the FULL reservoir mark.
9. Fill in a liquid in a radiator. On 4-cylinder Odysseys, watch the fluid coming out of the vent fitting, tighten the fitting when fluid flows out of it.
10. Start the engine and warm up the fluid until the fan turns on twice. Top up fluid if the level drops. Close the radiator cap.
Flushing the cooling system
1. Drain the liquid, close the tap and fill the cooling system with water or cleaner (in the latter case, remove the thermostat and reinstall the thermostat housing).
2. Run the engine for a few minutes and drain the water (cleaner by opening the radiator tap. Repeat the procedure until clean water flows from the radiator.
3. Rinse the expansion tank with clean water. Reinstall the removed parts.
4. Fill the system with coolant.