GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
Vehicle Care 291
{ WarningOperating the engine with the air
cleaner/filter off can cause you or
others to be burned. The air
cleaner not only cleans the air; it
helps to stop flames if the engine
backfires. Use caution when
working on the engine and do not
drive with the air cleaner/filter off.
CautionIf the air cleaner/filter is off, dirt
can easily get into the engine,
which could damage it. Always
have the air cleaner/filter in place
when driving.
Cooling System The cooling system allows the
engine to maintain the correct
working temperature. 1. Coolant Surge Tank
2. Coolant Surge Tank
Pressure Cap
3. Engine Electric
Cooling Fan(s)
{ Warning
An underhood electric fan can
start up even when the engine is
not running and can cause injury.
Keep hands, clothing, and tools
away from any underhood
electric fan. { WarningDo not touch heater or radiator
hoses, or other engine parts.
They can be very hot and can
burn you. Do not run the engine if
there is a leak; all coolant could
leak out. That could cause an
engine fire and can burn you. Fix
any leak before driving the
vehicle.
Engine Coolant The cooling system in the vehicle is
filled with DEX-COOL engine
coolant. This coolant is designed to
remain in the vehicle for 5 years or
240 000 km (150,000 mi), whichever
occurs first.
The following explains the cooling
system and how to check and add
coolant when it is low. If there is a
problem with engine overheating,
see Engine Overheating 0 294 .
GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
Vehicle Care 293the full cold mark. If it is not, there
may be a leak in the cooling
system.
If coolant is visible but the coolant
level is not at or above the full cold
mark, see “ How to Add Coolant to
the Coolant Surge Tank, ” following.
How to Add Coolant to the
Coolant Surge Tank
{ WarningSpilling coolant on hot engine
parts can burn you. Coolant
contains ethylene glycol and it will
burn if the engine parts are hot
enough.
{ Warning
Plain water, or other liquids such
as alcohol, can boil before the
proper coolant mixture will. With
plain water or the wrong mixture,
the engine could get too hot but
there would not be an overheat
(Continued) Warning (Continued) warning. The engine could catch
fire and you or others could be
burned.
{ WarningSteam and scalding liquids from a
hot cooling system are under
pressure. Turning the pressure
cap, even a little, can cause them
to come out at high speed and
you could be burned. Never turn
the cap when the cooling system,
including the pressure cap, is hot.
Wait for the cooling system and
pressure cap to cool.
Caution
Failure to follow the specific
coolant fill procedure could cause
the engine to overheat and could
(Continued) Caution (Continued) cause system damage. If coolant
is not visible in the surge tank,
contact your dealer.
If no coolant is visible in the surge
tank, add coolant.
1. Remove the coolant surge tank
pressure cap when the cooling
system, including the coolant
surge tank pressure cap and
upper radiator hose, is no
longer hot.
Turn the pressure cap slowly
counterclockwise about one full
turn. If a hiss is heard, wait for
that to stop. A hiss means
there is still some pressure left.
2. Keep turning the pressure cap
slowly, and remove it.
