Honda GX360 Owner's Manual page 38

SERVICING YOUR HONDA ENGINE
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 the reserve tank.
Wait untill the engine is cool. Without pressing down on the cap, turn
it counterclockwise untill it stops. After any remaining pressure has
been relieved, remove the cap by pressing down and again turning it
counterclockwise. Add enough coolant to fill the the radiator, and
reinstall the cap.
Fill
the reserve tank to the
MAX
mark after the engine
I
reaches normal operating temperature.
Removing the radiator cap while the
engine is hot can cause the coolant
to spray out, seriously scalding you.
Always let the engine cool down
before removing the radiator cap.
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