Chevrolet 2003 Malibu Owner's Manual page 239

2. Then keep turning the
pressure cap slowly,
and remove it.
3. Then fill the coolant surge tank with the proper
mixture, to the hash mark on the label. Wait about
five minutes, then check to see if the level is below
the hash mark. If the level is below the hash mark,
add additional coolant to bring the level up to the
hash mark. Repeat this procedure until the level
remains constant at the hash mark for at least
five minutes.
5-30