Honda 2017 Civic Owner's Manual page 547

uuMaintenance Under the HooduEngine Coolant
■
Adding the Coolant
Reserve Tank Cap
546
1. Make sure the engine and radiator are
cool.
2. Turn the reserve tank cap 1/8 of a turn
counterclockwise and relieve any pressure
in the cooling system. Do not push the cap
down when turning.
3. Push down and turn the reserve tank cap
counterclockwise to remove it.
4. Pour coolant into the reserve tank until it
reaches the MAX mark.
5. Put the reserve tank cap back on, and
tighten it fully.
1Engine Coolant
Do not add rust inhibitors or other additives to your
vehicle's cooling system. They may not be compatible
with the coolant or with the engine components.
1Adding the Coolant
NOTICE
Pour the fluid slowly and carefully so you do not spill
any. Clean up any spills immediately; they can
damage components in the engine compartment.