Pontiac 2005 Bonneville - Manual (Page 306)

8. Then fill the coolant recovery tank to the
FULL COLD mark.
9. Put the cap back on the coolant recovery tank,
but leave the radiator pressure cap off.
10. Start the engine and let it run until you can feel the
upper radiator hose getting hot. Watch out for the
engine cooling fans.
11. 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.
12. 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 the arrow on the pressure cap lines
up properly.
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