GMC Safari 2003 Owner's Manual page 250

If there seems to be no leak, start the engine again.
The engine cooling fan speed should increase when idle
speed is doubled by pushing the accelerator pedal
down. If it doesn't, your vehicle needs service. Turn off
the engine.
Notice: Engine damage from running your engine
without coolant isn't covered by your warranty.
Notice: When adding coolant, it is important that
you use only DEX-COOL
If coolant other than DEX-COOL
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.
Damage caused by the use of coolant other
®
than DEX-COOL is not covered by your new vehicle
warranty.
5-34
®
(silicate-free) coolant.
®
is added to
How to Add Coolant to the Coolant
Recovery Tank
If you haven't found a problem yet, but the coolant level
isn't at the ADD mark, add a 50/50 mixture of clean
drinkable water , and DEX-COOL
coolant recovery tank. See Engine Coolant on
page 5-28 for more information.
{
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
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
®
engine coolant at the
®
coolant.