Buick 2005 Century - Manual (Page 233)

Notice: If you use an improper coolant mixture,
your engine could overheat and be badly damaged.
The repair cost would not be covered by your
warranty. Too much water in the mixture can freeze
and crack the engine, radiator, heater core and
other parts.
If coolant has to be added more than four times a year,
have your dealer check the cooling system.
Notice: If you use the proper coolant, you do not
have to add extra inhibitors or additives which claim
to improve the system. These can be harmful.
Checking Coolant
The engine coolant recovery tank is located on the
passenger’s side of the vehicle at the rear of the engine
compartment. See Engine Compartment Overview on
page 5-12 for more information on location.
The vehicle must be
on a level surface.
When the engine is cold,
the coolant level should be
at the COLD mark or a
little higher.
When the engine is warm, the level should be up to the
HOT mark or a little higher.
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