GMC Canyon Owner's Manual page 344

How to Add Coolant to the Coolant
Recovery Tank
If you have not found a problem yet, but the
coolant level is not at the FULL COLD mark, add
a 50/50 mixture of clean, drinkable water and
®
DEX-COOL engine coolant at the coolant
recovery tank. See Engine Coolant on page 337
for more information.
344
CAUTION:
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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 proper coolant mixture. With
plain water or the wrong mixture, your
engine could get too hot but you would
not get the overheat warning. Your engine
could catch fire and you or others could
be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
®
coolant.