Page 156 of 376

Oil Pressure Gage
The engine oil pressure
gage, on the lower right
portion of your instrument
panel cluster, shows
engine oil pressure in psi
(pounds per square inch) or
in kPa (kilopascals).
Oil pressure may vary with outside temperature and oil
viscosity, but readings of 30 to 40 psi (205 to 275 kPa)
on gasoline engines at operating temperature and
moderate road speeds are normal. If you have a diesel
engine, the normal operating range should be between
35 and 70 psi (240 to 480 kPa).A reading in the low pressure zone may be caused by a
dangerously low oil level or other problem.
If you have a Caterpillar®diesel engine, also see your
Caterpillar®Operation & Maintenance Manual.
{CAUTION:
Do not keep driving if the oil pressure is low. The
engine can become so hot that it catches fire.
Someone could be burned. Check the oil as soon
as possible and have the vehicle serviced.
Notice:Lack of proper engine oil maintenance can
damage the engine. The repairs would not be
covered by the vehicle warranty. Always follow the
maintenance schedule in this manual for changing
engine oil.
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Page 228 of 376
What Kind of Engine Oil to Use
Look for three things:
•CJ-4
Oils designated as API CJ-4 are required for the
vehicle. The CJ-4 designation can appear either alone
or in combination with other American Petroleum
Institute (API) designations, such as API CJ-4/SL.
These letters show API levels of quality.
•SAE 15W-40
SAE 15W-40 is best for the vehicle. When it is very
cold, below 0°F (−18°C), use SAE 5W-40 to improve
cold starting. These numbers on the oil container
show its viscosity, or thickness. Do not use other
viscosity oils such as SAE 10W-30, SAE 10W-40, or
SAE 20W-50.
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Page 232 of 376
What Kind of Engine Oil to Use
Look for three things:
•CJ-4
Oils designated as API CJ-4 are required for the
vehicle. The CJ-4 designation can appear either alone
or in combination with other American Petroleum
Institute (API) designations, such as API CJ-4/SL.
These letters show API levels of quality.
•SAE 10W-40 or SAE 15W-40
SAE 10W-40 or SAE 15W-40 is best for the
vehicle. When it is very cold, below 0°F (−18°C), use
SAE 5W-40 to improve cold starting. These numbers
on the oil container show its viscosity, or thickness.
Do not use other viscosity oils such as SAE 10W-30
or SAE 20W-50.
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Page 236 of 376

What Kind of Engine Oil to Use
Look for three things:
•GM6094M
Use only an oil that meets GM Standard GM6094M.
•SAE 5W-30
SAE 5W-30 is best for the vehicle. These numbers
on an oil container show its viscosity, or thickness.
Do not use other viscosity oils such as SAE 20W-50.
•American Petroleum Institute (API) starburst symbol
Oils meeting these
requirements should have
the starburst symbol on the
container. This symbol
indicates that the oil has
been certified by the
American Petroleum
Institute (API).
Notice:Use only engine oil identified as meeting
GM Standard GM6094M and showing the American
Petroleum Institute Certified For Gasoline Engines
starburst symbol. Failure to use the recommended
oil can result in engine damage not covered by
the vehicle warranty.
Cold Temperature Operation
If in an area of extreme cold, where the temperature
falls below−20°F (−29°C), use either an SAE 5W-30
synthetic oil or an SAE 0W-30 engine oil. Both provide
easier cold starting for the engine at extremely low
temperatures. Always use an oil that meets the required
specification, GM6094M. See “What Kind of Engine
Oil to Use” for more information.
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Page 345 of 376

Part C: Recommended Fluids and
Lubricants
Fluids and lubricants identified below by name, part
number, or specification can be obtained from your
dealer/retailer.
Usage Fluid/Lubricant
Engine Oil
(Gasoline
Engine)Engine oil which meets GM Standard
GM6094M and displays the
American Petroleum Institute (API)
Certified for Gasoline Engines
starburst symbol. To determine the
proper viscosity for your vehicle’s
engine, see “Engine Oil” in the Index.
Engine Oil
(DURAMAX
®/
Isuzu Diesel
Engines)Engine oils with the letters CJ-4 are
required for your vehicle. The CJ-4
designation can appear either alone
or in combination with other
American Petroleum Institute (API)
designations, such as API CJ-4/SL.
These letters show API levels of
quality. To determine the preferred
viscosity for your vehicle’s diesel
engine, see “Engine Oil” in the Index.
Engine Oil
(Caterpillar
®
Diesel Engine)See the Caterpillar
®Operation &
Maintenance Manual for engine oil
recommendations.
Usage Fluid/Lubricant
Engine Coolant
(Caterpillar
®
Diesel Engine)See the Caterpillar
®Operation &
Maintenance Manual for engine
coolant recommendations.
Engine Coolant
(Gasoline
Engine &
DURAMAX
®/
Isuzu Diesel
Engines)50/50 mixture of clean, drinkable
water and use only DEX-COOL
®
Coolant. SeeEngine Coolant
(Caterpillar Diesel Engines) on
page 5-47.
Hydraulic Brake
SystemDelco
®Supreme 11 Brake Fluid or
equivalent DOT-3 brake fluid.
Windshield
Washer SolventOptikleen
®Washer Solvent.
Clutch Bearing
LubricantClutch Bearing Lubricant (GM Part
No. 12378484 or equivalent NLGI
#3 consistency).
Exhaust Brake
Ball Joint Cap
LubricantHigh-Temperature Grease
(GM Part No. U.S. 1051344,
in Canada 903037) or NLGI #3
consistency.
Power Steering
SystemDEXRON
®-VI Automatic
Transmission Fluid.
Manual
TransmissionSynthetic Manual Transmission Fluid
(GM Part No. U.S. 88861952,
in Canada 88861953).
Automatic
TransmissionSee the Allison Transmission
®
Operator’s Manual for correct
transmission fluid.
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