The first recommended cooling system fluid change is 45,000 miles (72,000 km) or 3 years whichever occurs first. Thereafter, the interval is every 30,000 miles (48,000 km) or 2 years, whichever occurs first. The cooling system should be inspected, flushed and refilled with fresh coolant during these maintenance intervals.
The manufacturer recommends using 50% Honda Antifreeze/Coolant mixed with 50% water. A high quality major-brand, non-silicate designed for use in aluminum engines can be substituted temporarily. Using distilled water instead of regular tap water to mix with the antifreeze will also help to keep the cooling system corrosion free, as some of the chemicals found in tap water may corrode aluminum. In addition, if the coolant is left in the system too long, it loses its ability to prevent rust and corrosion.
To check the coolant level, simply verify whether the coolant is up to the FULL line on the expansion tank. Add the proper mixture of coolant to the expansion tank if the level is low. Never add cold water or coolant to a hot engine as damage to both the cooling system and the engine could result.
The radiator cap should be removed only for cleaning or draining the system. The cooling system is under pressure when hot. Removing the radiator cap when the engine is warm or overheated will cause coolant to spill or be forced out, possibly causing serious burns. The system should be allowed to cool before attempting removal of the radiator cap or other cooling system components.
If any coolant spills on painted portions of the body, rinse it off immediately.
DRAIN & REFILL
- Before draining the cooling system, place the heater's temperature selector to the full WARM position while the engine is running.
- Turn the engine off before it gets hot and the system builds pressure.
- Make sure the engine is still cool and the vehicle is parked on a level surface.
- Remove and drain the reservoir recovery tank.
- Place a fluid catch pan under the radiator. Turn the radiator draincock counterclockwise to open, then allow the coolant to drain.
Remove the radiator cap by performing the following:
- Slowly rotate the cap counterclockwise to the detent.
- If any residual pressure is present, WAIT until the hissing stops.
- After the hissing noise has ceased, press down on the cap and continue rotating it counterclockwise to remove it.
See Figures 1 and 2
- Allow the coolant to drain completely from the vehicle.
- Close the radiator draincock.
When filling the cooling system, be careful not to spill any coolant on the drive belts or alternator.To refill:
- Make sure the heater temperature is placed in the full hot position.
- On 4-cylinder Odyssey models, open the bleed screw on the thermostat housing.
- Install the reservoir recovery tank and using a 50/50 mixture of the recommended antifreeze and clean water, fill the cooling system reservoir tank to the FULL mark.
- Begin filling the radiator with the 50/50 mixture of coolant. On 4-cylinder Odyssey models, watch for air being released from the open the bleed screw on the thermostat housing. Once coolant mixture begins to steadily flow through the bleeder, close the bleeder.
- Continue to fill the radiator until the radiator is full.
- Start the engine and allow the engine to run until the cooling fans operate two times, making sure to top off the system as the fluid level drops.
See Figures 3 and 4
- After the cooling fan has run for the second time, top off the system as necessary, then install the radiator cap.
- Allow the engine to run and inspect the cooling system for leaks.
FLUSHING & CLEANING
- Drain the cooling system, as described in the preceding drain and refill procedure.
- Close the drain valve.
A flushing solution may be used. Ensure that it is safe for use with aluminum cooling system components, and follow the directions on the container.
- If using a flushing solution, remove the thermostat, then reinstall the thermostat housing.
- Add sufficient water to fill the system.
- Start the engine and run it for a few minutes. Drain the system.
- Allow the water to flow out of the radiator until it is clear.
- Reconnect the heater hose.
- Drain the cooling system.
- Reinstall the thermostat.
- Empty the coolant reservoir or surge tank and flush it.
- Fill the cooling system, using the correct ratio of antifreeze and water, to the bottom of the filler neck. Fill the reservoir or surge tank to the FULL mark.
- Install the radiator cap.