Honda Civic Service Manual: Engine Cooling

Engine

...

Coolant Replacement (R18A9)

1. Radiator Cap 1. Wait until the engine is cool, then carefully remove the radiator cap. ...

See also:

Honda Civic Service Manual. High Mount Brake Light Removal and Installation - With Trunk Lid Spoiler (2-door)
Removal 1. High Mount Brake Light 1. Remove the covers (A). 2. Remove the high mount brake light (B) from the trunk lid spoiler. ...