Acura 2008 RL - Manual (Page 408)

If the coolant level in the reserve
tank is at or below the MIN line, add
coolant to bring it up to the MAX line.
Inspect the cooling system for leaks.
If the reserve tank is completely
empty, you should also check the
coolant level in the radiator.
If Honda antifreeze/coolant is not
available, you may use another
major-brand non-silicate coolant as a
temporary replacement. Make sure it
is a high-quality coolant
recommended for aluminum engines.
Continued use of any non-Honda
coolant can result in corrosion,
causing the cooling system to
malfunction or fail. Have the cooling
system flushed and refilled with
Honda antifreeze/coolant as soon as
possible.
Always use Honda Long-life Anti-
freeze/Coolant Type 2. This coolant
is pre-mixed with 50 percent
antifreeze and 50 percent water.
Never add straight antifreeze or
plain water. Adding Engine Coolant
Engine Coolant
402
RESERVE TANK
Removing the radiator cap
while the engine is hot can
cause the coolant to spray out,
seriously scalding you.
Always let the engine and
radiator cool down before
removing the radiator cap.