GMC 2008 Acadia - Manual (Page 346)

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 filler
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. 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 to secure it tightly.
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