Pontiac Grand Prix 2007 Owner's Manual page 380

12. Then replace the 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.
13. Check the coolant in the recovery tank. The
level in the coolant recovery tank should be
at the cold fill line when the engine is cold.
How to Add Coolant to the Cooling
System (5.3L V8 Engine)
Notice: Your engine has a specific cooling
system drain and fill procedure. Failure
to follow this procedure could cause your
engine to overheat and be severely damaged.
If your engine's cooling system needs to
be drained and re-filled, please see your
dealer/retailer.
380
1. If you hear a hiss, wait for that to stop. A hiss
means that there is still some pressure left.
2. Then keep turning the pressure cap to remove
the pressure cap.
You can remove the
pressure cap when
the cooling system,
including the pressure
cap and upper radiator
hose is no longer hot.
Turn the pressure cap
slowly counterclockwise.