Pontiac 1997 Grand Prix Owner's Manual page 256

6. Then fill the coolant recovery tank.
7. Put the cap back on the coolant recovery tank, but
leave the pressure cap off.
8. Start the engine and let it run until you can feel the
upper radiator hose getting hot. Watch out
for the
engine fans,
9, By this time, the coolant level inside the radiator
filler neck may be lower. If the level is lower, add
more of the proper mix through the filler neck until
the level reaches the base of the filler neck.
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