Chevrolet 2003 Silverado Owner's Manual page 418

How to Add Coolant to the Coolant
Surge Tank Gasoline Engines
If you haven't found a problem yet, check to see if coolant
is visible in the surge tank. If coolant is visible but the
coolant level isn't at or above the FULL COLD mark, add
a 50/50 mixture of clean, drinkable water and
®
DEX-COOL coolant at the coolant surge tank, but be
sure the cooling system, including the coolant surge tank
pressure cap, is cool before you do it. See Engine
Coolant on page 5-30 for more information.
If no coolant is visible in the surge tank, add coolant as
follows:
{
CAUTION:
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.
5-38
{
CAUTION:
Adding only plain water to your cooling
system can be dangerous. Plain water, or
some other liquid such as alcohol, can boil
before the proper coolant mixture will. Your
vehicle's coolant warning system is set for the
CAUTION: (Continued)