Acura 2009 RL - Manual (Page 460)

The coolant level should be up to
the base of the filler neck. Add
coolant if it is low. When the radiator and engine are
cool, relieve any pressure in the
cooling system by turning the
radiator cap counterclockwise,
without pressing down.
Remove the radiator cap by
pushing down and turning
counterclockwise.
Lift up the lid on the front
bulkhead cover from the front.
Pour the coolant slowly and
carefully so you do not spill any.
Clean up any spill immediately; it
could damage components in the
engine compartment.
3.
2. 1. 4.
Engine Coolant
454
LID RADIATOR CAP
RESERVE TANK