Page 231 of 384
Look for this information on the oil container, and use
only those oils that are identified as meeting GM
Standard GM6094M and have the starburst symbol on
the front of the oil container.
Notice:Use only engine oil identi ed as meeting
GM Standard GM6094M and showing the American
Petroleum Institute Certi ed For Gasoline Engines
starburst symbol. Failure to use the recommended
oil can result in engine damage not covered by
your warranty.If you are in an area of extreme cold, where the
temperature falls below−20°F (−29°C), it is
recommended that you use either an SAE 5W-30
synthetic oil or an SAE 0W-30 oil. Both provide easier
cold starting and better protection for the engine at
extremely low temperatures.
Engine Oil Additives
Do not add anything to the oil. The recommended oils
with the API service symbol are all you need for
good performance and engine protection.
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Page 232 of 384

Engine Oil (DURAMAX®Diesel
Engine)
Checking Engine Oil
It is a good idea to check the engine oil level every time
you get fuel.
The engine oil dipstick is
located in the engine
compartment on the driver
side of the vehicle.
In order to get an accurate reading, the engine should
be at normal operating temperature, so that the oil
is warm, and the vehicle must be on level ground.
1. If the engine is at normal operating temperature and
the oil is warm, turn off the engine and allow at
least five minutes for the oil to drain back into the
oil pan. If you do not do this, the oil dipstick
might not show the actual level.If the engine has not been run long enough to bring
it up to normal operating temperature and the oil
is cool, turn off the engine and allow 30 minutes for
the oil to drain back into the oil pan. If you do not do
this, the oil dipstick might not show the actual level.
2. Pull out the dipstick and clean it with a paper towel
or a cloth, then push it back in all the way.
3. Remove the dipstick again, keeping the tip down,
and check the oil level.
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When to Add Engine Oil
If the oil is below the cross-hatched area at the tip of
the dipstick, add at least two quarts/liters of the
recommended oil. This section explains what kind of oil
to use. For engine oil crankcase capacity, see
Capacities and Specifications on page 5-109.
Notice:Do not add too much oil. If the engine has
so much oil that the oil level gets above the
cross-hatched area that shows the proper operating
range, the engine could be damaged.Add oil at the engine oil fill
cap in the engine
compartment. Install and
fully tighten the fill cap
when you are through.
Be sure to add enough oil to put the level somewhere in
the proper operating range. Push the dipstick all the
way back in when you are through.
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Page 234 of 384
What Kind of Engine Oil to Use
Look for three things:
•CJ-4
Oils designated as API 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.
Notice:Use only engine oils that have the
designation CJ-4 for the diesel engine. Failure to
use the recommended oil can result in engine
damage not covered by your warranty.
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Page 235 of 384

•SAE 15W-40
As shown in the viscosity chart, SAE 15W-40 is best
for your vehicle. When it is very cold, below 0°F
(−18°C), you should 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.
This doughnut-shaped
logo (symbol) is used on
most oil containers to help
you select the correct oil. It
means that the oil has been
certified by the American
Petroleum Institute.
Look for this on the oil container, and use only those
oils that display this logo.Engine Oil Additives
Do not add anything to the oil. The recommended oils
with the API service symbol are all you need for good
performance and engine protection.
When to Change Engine Oil (Vehicles
Without the Engine Oil Life System)
Change the engine oil and filter every 15,000 miles
(24 000 km), or every 12 months, or every 750 hours of
engine operation, whichever occurs first. See
Scheduled Maintenance on page 6-5.
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Page 236 of 384

Engine Oil (Isuzu Diesel Engine)
Checking Engine Oil
It is a good idea to check the engine oil level every time
you get fuel.
The engine oil dipstick is
located in the engine
compartment on the driver
side of the vehicle.
In order to get an accurate reading, the engine should
be at normal operating temperature, so that the oil
is warm, and the vehicle must be on level ground.
1. If the engine is at normal operating temperature and
the oil is warm, turn off the engine and allow at
least five minutes for the oil to drain back into the oil
pan. If you do not do this, the oil dipstick might not
show the actual level.If the engine has not been run long enough to bring
it up to normal operating temperature and the oil
is cool, turn off the engine and allow 30 minutes for
the oil to drain back into the oil pan. If you do not do
this, the oil dipstick might not show the actual level.
2. Pull out the dipstick and clean it with a paper towel
or a cloth, then push it back in all the way.
3. Remove the dipstick again, keeping the tip down,
and check the oil level.
When to Add Engine Oil
Notice:Do not add too much oil. Keep the oil level
between the ADD and FULL marks on the dipstick.
Under normal engine operation, the engine oil
level can increase above the FULL mark as a result
of DPF regeneration. A small increase in the oil
level is normal. If the engine has so much oil that
the oil level reaches the wider portion (A) on the
dipstick, the engine oil must be changed as soon as
possible or the engine could be damaged.
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Page 237 of 384
If the oil is below the ADD
mark on the dipstick, add
at least one quart/liter
of the recommended oil.
This section explains what kind of oil to use. For engine
oil crankcase capacity, seeCapacities and
Specifications on page 5-109.Add oil at the engine oil fill
cap in the engine
compartment. Install and
fully tighten the fill cap
when you are through.
Be sure to add enough oil to put the level somewhere in
the proper operating range. Push the dipstick all the
way back in when you are through.
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Page 238 of 384
What Kind of Engine Oil to Use
Look for three things:
•CJ-4
Oils designated as API 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.
Notice:Use only engine oils that have the
designation CJ-4 for the diesel engine. Failure to
use the recommended oil can result in engine
damage not covered by your warranty.
5-34