Honda H6522 Owner's Manual page 45

If there is no coolant in the reserve tank, the cooling system should be
checked for leaks and repaired if necessary. Coolant must then be added
to the radiator and reserve tank.
m
The coolant is hot and under pressure and severe scalding
could result. Never remove the radiator cap when the engine is hot.
Wait until the engine is cool, then turn the radiator cap counterclockwise
until it stops. DO NOT PRESS DOWN WHILE TURNING THE CAP. After
any remaining pressure has been relieved, remove the cap by pressing
down and again turning it counterclockwise. Add enough coolant to fill the
radiator, and reinstall the cap. Be sure to tighten it securely. Fill the reserve
tank up to the MAX level with the engine cold. Recheck the reserve tank
once the engine reaches normal operating temperature.
RADlAiOR CAP
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