GMC 2004 Sierra 1500 Pickup Owner's Manual page 447

Open the cap with the washer symbol on it. Add washer
fluid until the tank is full.
The windshield washer
fluid reservoir is located in
the engine compartment
toward the front of the
vehicle on the driver's side.
Notice:
•
When using concentrated washer fluid, follow
the manufacturer's instructions for adding
water.
•
Do not mix water with ready-to-use washer fluid.
Water can cause the solution to freeze and
damage your washer fluid tank and other parts
of the washer system. Also, water does not
clean as well as washer fluid.
•
Fill your washer fluid tank only three-quarters
full when it is very cold. This allows for
expansion if freezing occurs, which could
damage the tank if it is completely full.
•
Do not use engine coolant (antifreeze) in your
windshield washer. It can damage your washer
system and paint.
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