2002 GMC YUKON fuel additives

6-5 Additives
Some gasolines that are not reformulated for low
emissions may contain an octane
-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask the attendant where you buy gasoline
whether the fuel contains MMT. General Motors does
not recommend the use of such gasolines. Fuels
containing MMT can reduce the life of spark plugs and
the performance of the emission control system may be
affected. The malfunction indicator lamp may turn on.
If this occurs, return to your authorized GM dealer
for service.
To provide cleaner air, all gasolines in the United States
are now required to contain additives that will help
prevent engine and fuel system deposits from forming,
allowing your emission control system to work properly.
You should not have to add anything to your fuel.
Gasolines containing oxygenates, such as ethers and
ethanol, and reformulated gasolines may be available in
your area to contribute to clean air. General Motors
recommends that you use these gasolines, particularly if
they comply with the specifications described earlier.
NOTICE:
Your vehicle was not designed for fuel that
contains methanol. Don't use fuel containing
methanol. It can corrode metal parts in your
fuel system and also damage plastic and rubber
parts. That damage wouldn't be covered under
your warranty.
Fuel E-85 (85% Ethanol)
The 8th digit of your vehicle identification number
(VIN) shows the code letter or number that identifies
your engine. You will find the VIN at the top left of the
instrument panel. See ªVehicle Identification Numberº
in the Index.
If your vehicle has the 5.3L V8 engine (VIN Code Z
only), you may use either regular unleaded gasoline or
ethanol fuel containing up to 85% ethanol (E
-85); also
see ªFuel (Gasoline)º listed previously. In all other
engines, including the 5.3L V8 (Code T), use only
regular unleaded gasoline.

6-6
Only vehicles that have the 5.3L V8 engine
(VIN Code Z) may use 85% ethanol fuel (E
-85).
Many service stations will not have an 85% ethanol
fuel (E
-85) pump available. The U. S. Department
of Energy has an alternative fuels website
(http://afdcmap.nrel.gov/nrel/) that can help you find
E
-85 fuel. Those stations that do have E-85 should
have a label indicating ethanol content. Do not use the
fuel if the ethanol content is greater than 85%.
Your vehicle may not operate properly if the ethanol
content is greater than 85%.
At a minimum, E
-85 should meet ASTM
Specification D 5798.
To insure quick starts in the wintertime, the E
-85 fuel
must be formulated properly for your climate according
to ASTM specification D 5798. If you have trouble
starting on E
-85, it may be because your E-85 fuel is not
properly formulated for your climate. If this happens,
switching to gasoline or adding gasoline to your fuel
tank may improve starting. Your vehicle is designed to
accommodate a mixture of gasoline and E
-85 fuel. For
good starting and heater efficiency below 32
F (0
C),
the fuel mix in the fuel tank should contain no more than
70% ethanol.E
-85 has less energy per gallon than gasoline, so you'll
need to refill your fuel tank more often when using E
-85
than when you're using gasoline. Regular unleaded
gasoline is recommended when pulling a trailer. For
payload capacity with ethanol fuel see ªLoading Your
Vehicleº in the Index.
NOTICE:
Some additives are not compatible with E-85 fuel and
may harm your fuel system. Damage caused by
additives wouldn't be covered by your new vehicle
warranty. Don't use additives with E
-85 fuel.
NOTICE:
Your vehicle was not designed for fuel that contains
methanol. It can corrode metal parts in your fuel
system and also damage plastic and rubber parts.
That damage wouldn't be covered under your
warranty. Don't use fuel containing methanol.

6-19
As in the chart shown previously, SAE 5W-30 is best for
your vehicle. However, you can use SAE 10W
-30 if it's
going to be 0
F (
-18
C) or above. These numbers on an
oil container show its viscosity, or thickness. Do not use
other viscosity oils, such as SAE 20W
-50.
NOTICE:
Use only engine oil with the American Petroleum
Institute Certified For Gasoline Engines
starburst symbol. Failure to use the
recommended oil can result in engine damage not
covered by your warranty.
GM Goodwrench
oil meets all the requirements for
your vehicle.
If you are in an area where the temperature falls below
-20F (-29C), consider using either an SAE 5W-30
synthetic oil or an SAE 0W
-30 oil. Both will provide
easier cold starting and better protection for your engine
at extremely low temperatures.
Engine Oil Additives
Don't add anything to your oil. The recommended oils
with the starburst symbol are all you will need for good
performance and engine protection.
When to Change Engine Oil
(GM Oil Life System)
Your vehicle has a computer system that lets you know
when to change the engine oil and filter. This is based on
engine revolutions and engine temperature, and not on
mileage. Based on driving conditions, the mileage at
which an oil change will be indicated can vary
considerably. For the oil life system to work properly,
you must reset the system every time the oil is changed.
When the system has calculated that oil life has been
diminished, it will indicate that an oil change is
necessary. A CHANGE ENGINE OIL message will
come on. Change your oil as soon as possible within the
next two times you stop for fuel. It is possible that, if
you are driving under the best conditions, the oil life
system may not indicate that an oil change is necessary
for over a year. However, your engine oil and filter must
be changed at least once a year and at this time the
system must be reset. It is also important to check your
oil regularly and keep it at the proper level.
If the system is ever reset accidentally, you must change
your oil at 3,000 miles (5 000 km) since your last oil
change. Remember to reset the oil life system whenever
the oil is changed.