GMC 1996 Sierra Owner's Manual page 230

NOTICE:
I
I
I
Engine damage from running your engine
without coolant isn't covered by your warranty.
If there seems to be no leak, start the engine again. See
if the fan speed increases when idle speed is doubled by
pushing the accelerator pedal down. If it doesn't, your
vehicle needs service. Turn off the engine.
How to Add Coolant to the Coolant
Recovery Tank
If you haven't found
a
problem yet,
but
the coolant level
isn't at or above the COLD mark, add a SO/SO mixture
of ciecu? w t e r (preferably distilled) and DEX-COOL"
(orange-colored, silicate-free) antifreeze at the coolant
recovery tank. (See ('Engine Coolant" in the Index for
more information.)
I
A
CAUTION:
Adding only plain water to your cooling system
can be dangerous. Plain water, or some other
liquid like alcohol, can boil before the proper
coolant mix will. Your vehicle's coolant warning
system is set for the proper coolant mix. With
plain water or the wrong mix, your engine could
get too hot but you wouldn't get the overheat
warning. Your engine could catch fire and you or
others could be burned. Use a 50/50
mix
of
clean
water and DEX-COOL
TM
antifreeze.
I
NOTICE:
In
cold weather, water can freeze and crack
the engine, radiator, heater core and other parts.
Use the recommended coolant and the proper
coolant mix.
5- 14