Pontiac 2005 GTO - Manual (Page 219)

How to Add Coolant to the Radiator
Notice: Your engine has a specific radiator
fill procedure. Failure to follow this procedure could
cause your engine to overheat and be severely
damaged.
1. You can remove the radiator pressure cap when
the cooling system, including the radiator pressure
cap and upper radiator hose, is no longer hot.
See Engine Compartment Overview on page 5-12
for more information on the location of the
radiator pressure cap.
Turn the pressure cap slowly counterclockwise until
it first stops. Do not press down while turning the
pressure cap. If you hear a hiss, wait for that to stop.
A hiss means there is still some pressure left.
2. Then keep turning the pressure cap, but now push
down as you turn it. Remove the pressure cap.
3. Fill the radiator with the proper DEX-COOL ® coolant
mixture, up to the base of the filler neck. See
Engine Coolant on page 5-23 for more information
about the proper coolant mixture.
4. Rinse or wipe any spilled coolant from the engine
and the compartment.
5. Then fill the coolant overflow reservoir to the bottom
arrow on the dipstick.
6. Put the cap back on the coolant overflow reservoir,
but leave the radiator pressure cap off.
7. Start the engine and let it run until you can feel the
upper radiator hose getting hot. Watch out for the
engine cooling fan.
8. By this time, the coolant level inside the radiator fill
neck may be lower. If the level is lower, add more
of the proper DEX-COOL
® coolant mixture
through the filler neck until the level reaches the
base of the filler neck.
9. Then replace the radiator pressure cap. At any time
during this procedure, if coolant begins to flow out
of the filler neck, reinstall the pressure cap. Be
sure the pressure cap is hand-tight and fully seated.
10. Check the coolant in the overflow reservoir.
The level should be at the bottom arrow on
the dipstick when the engine is cold.
See your dealer, if necessary.
5-33