GMC 1993 Safari Owner's Manual page 218

Adding only plain water to your cooling system can be dangerous.
I
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 a proper antifreeze.
A
Plain water, or some other liquid like alcohol, can boil before the
I In cold weather, water can freeze and crack the engine, radiator, he?
core and other parts. Use the recommended coolant
PO408
I; -
contains ethylene glycol and it will burn if the engine parts are hot
You can be burned if you spill coolant on hot engine parts. Coolant
I
enough. Don't spill coolant on a hot engine.
When the coolant in the coolant recovery tank
is
at or above FULL, start
your vehicle.
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