GMC 2008 Canyon - Manual (Page 295)

4. Fill the coolant recovery tank to the
FULL COLD mark.
5. Reinstall the cap on the coolant recovery tank,
but leave the radiator pressure cap off.
6. Start the engine and let it run until you can feel
the upper radiator hose getting hot. Watch out
for the engine cooling fan.
7. By this time, the coolant level inside the radiator
filler neck might 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.
8. 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 to secure it tightly.
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