Buick 2004 Century - Manual (Page 246)

6. Then fill the coolant recovery tank to the COLD
mark on the coolant recovery tank.
7. Put the cap back on the coolant recovery tank, but
leave the radiator pressure cap off.
8. Start the engine and let it run until the upper
radiator hose feels it is getting hot. Watch out for the
engine cooling 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 DEX-COOL
® coolant mixture
through the filler neck until the level reaches
the base of the filler neck.
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