Chevrolet 2009 Silverado 1500 Crew Cab Owner's Manual page 52

How to Add Coolant to the DMCM
Coolant Surge Tank
If no problem has been found yet, check to see if
coolant is visible in the DMCM coolant surge tank. If
coolant is visible, add pre-mixed DEX-COOL™ coolant,
available at your dealer/retailer, at the DMCM coolant
surge tank, but be sure the DMCM cooling system,
including the DMCM coolant surge tank pressure cap, is
cool before you do it. Use the procedure following.
5-8
CAUTION:
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Steam and scalding liquids from a hot cooling
system can blow out and burn you badly. They are
under pressure, and if you turn the coolant surge
tank pressure cap — even a little — they can
come out at high speed. Never turn the cap when
the cooling system, including the coolant surge
tank pressure cap, is hot. Wait for the cooling
system and coolant surge tank pressure cap to
cool if you ever have to turn the pressure cap.
Notice: Using coolant other than a pre-mixed
DEX-COOL, available at your dealer/retailer, may
damage your vehicle. Any repairs would not be
covered by your warranty. Always use a pre-mixed
DEX-COOL (silicate-free) coolant in your vehicle.