GMC 1996 Sierra Owner's Manual page 277

A
50/50 mixture of water and the proper coolant for
your vehicle will:
Give freezing prorecrlon down to -34°F (-37°C).
Give boiling protection up to 265°F (129°C).
Protect against rust and corrosion.
Help keep the proper engine temperature.
Let the warning gages work as they should.
NOTICE:
When adding coolant it is important that you use
DEX-COOL
TM
(orange-colored, silicate-free)
coolant meeting GM Specification 6277M.
If silicated coolant is added to the system,
premature engine, heater core or radiator
corrosion may result. In addition, the engine
coolant will require change sooner
--
at
30,000 miles (50 000 km) or 24 months,
whichever occurs first.
use a mixture of one-half
d u m wwter
(preferably
distilled) and one-half DEX-COOL" (orange-colored.
silicate-free) antifreeze that meets GM Specification
6277M. which won't damage aluminum parts. Use
GM Engine Coolant Supplement (sealer) (GM Part
No. 363462 1
)
with any complete coolant change. If you
use this mixture. you don't need to add anything else.
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 50150 mix of clean
water and DEX-COOL
TM
(orange-colored,
silicate-free) antifreeze.
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