Honda Civic Service Manual: Engine Cooling

Engine

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Coolant Replacement (R18A9)

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

See also:

Honda Civic Owners Manual. RDM On and Off
Press the RDM button to turn the system on and off.  The indicator in the button comes on and the message appears on the driver information interface when the system is on. RDM On and Off When you have selected Warning Only from the customized options using th ...