2005 GMC YUKON XL low oil pressure

Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and the
REDUCED ENGINE POWER message is displayed, an
overheat protection mode which alternates ring
groups of cylinders helps prevent engine damage. In
this mode, you will notice a loss in power and engine
performance. This operating mode allows your vehicle to
be driven to a safe place in an emergency. Driving
extended miles (km) and/or towing a trailer in the
overheat protection mode should be avoided.
Notice:After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any repair.
The engine oil will be severely degraded. Repair the
cause of coolant loss, change the oil and reset the oil
life system. SeeEngine Oil on page 5-14.
Cooling System
When you decide it is safe to lift the hood, here is what
you will see:
A. Coolant Surge Tank
B. Coolant Surge Tank Pressure Cap
C. Electric Engine Cooling Fan (If Equipped)
5-30

{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 re and you or others
could be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
®coolant.
Notice:In cold weather, water can freeze and crack
the engine, radiator, heater core and other parts.
Use the recommended coolant and the proper
coolant mixture.
{CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol
and it will burn if the engine parts are hot
enough. Do not spill coolant on a hot engine.
1. You can 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 (left)
about one full turn. If you hear a hiss, wait for that
to stop. A hiss means there is still some pressure left.
2. Then keep turning the pressure cap slowly, and
remove it.
5-33

Fluid
Automatic Transmission................................5-22
Power Steering...........................................5-35
Windshield Washer......................................5-37
Fog Lamps....................................................3-17
Front Axle......................................................5-48
Fuel............................................................... 5-5
Additives...................................................... 5-6
California Fuel.............................................. 5-6
Filling a Portable Fuel Container..................... 5-9
Filling Your Tank........................................... 5-8
Fuels in Foreign Countries.............................. 5-7
Gage.........................................................3-45
Gasoline Octane........................................... 5-5
Gasoline Specications.................................. 5-5
Low Warning Light.......................................3-45
Fuses
Center Instrument Panel Fuse Block.............5-108
Fuses and Circuit Breakers.........................5-105
Instrument Panel Fuse Block.......................5-106
Underhood Fuse Block...............................5-109
Windshield Wiper.......................................5-105
G
Gage
Engine Coolant Temperature.........................3-37
Fuel..........................................................3-45
Oil Pressure...............................................3-42Gage (cont.)
Speedometer..............................................3-30
Tachometer.................................................3-30
Transmission Temperature.............................3-37
Voltmeter Gage...........................................3-34
Garage Door Opener.......................................2-39
Gasoline
Octane........................................................ 5-5
Specications............................................... 5-5
Glove Box.....................................................2-43
GM Mobility Reimbursement Program.................. 7-5
H
Hazard Warning Flashers................................... 3-6
Head Restraints............................................... 1-7
Headlamps............................................3-14, 5-50
Automatic Headlamp System.........................3-16
Bulb Replacement.......................................5-50
Daytime Running Lamps...............................3-15
Flash-to-Pass............................................... 3-9
Front Turn Signal, Sidemarker and Daytime
Running Lamps........................................5-51
Halogen Bulbs............................................5-50
High/Low Beam Changer................................ 3-8
On Reminder..............................................3-15
Heated Seats................................................... 1-5
Heater...........................................................3-20
Highbeam On Light.........................................3-44
6