Pontiac 2004 Grand Am - Manual (Page 258)

1. Park the vehicle on a level surface.
You can remove the coolant surge tank pressure
cap when the cooling system, including the coolant
surge tank pressure cap and upper radiator
hose, is no longer hot.
2. Turn the pressure cap slowly counterclockwise (left)
about two or two and one-half turns. If you hear a
hiss, wait for that to stop. This will allow any pressure
still left to be vented out the discharge hose.
3. Keep turning the
pressure cap slowly,
and remove it.
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