Take care not to spill gasoline during refu-
eling. Gasoline containing oxygenates can
cause paint damage.
Aftermarket fuel additives
NISSAN does not recommend the use of any fuel
additives (for example, fuel injector cleaner, oc-
tane booster, intake valve deposit removers, etc.)
which are sold commercially. Many of these ad-
ditives intended for gum, varnish or deposit re-
moval may contain active solvents or similar in-
gredients that can be harmful to the fuel system
and engine.
Octane rating tips
In most parts of North America, you should use
unleaded gasoline with an octane rating of at
least 87 (except supercharger) or 91 (super-
charger ) AKI (Anti-Knock Index) . However, you
may use unleaded gasoline with an octane rating
as low as 85 AKI (Anti-Knock Index) number in
high altitude areas [over 4,000 ft (1,219 m)] such
as: Colorado, Montana, New Mexico, Utah, Wyo-
ming, northeastern Nevada, southern Idaho,
western South Dakota, western Nebraska, and
the part of Texas which is directly south of New
Mexico.
Using unleaded gasoline with an octane
rating lower than stated above can cause
persistent, heavy “spark knock.” (“Sparkknock” is a metallic rapping noise.) If se-
vere, this can lead to engine damage. If you
detect a persistent heavy spark knock even
when using gasoline of the stated octane
rating, or if you hear steady spark knock
while holding a steady speed on level
roads, have a NISSAN dealer correct the
condition. Failure to correct the condition
is misuse of the vehicle, for which NISSAN
is not responsible.
Incorrect ignition timing may result in spark
knock, after-run and/or overheating, which may
cause excessive fuel consumption or engine
damage. If any of the above symptoms are en-
countered, have your vehicle checked at a
NISSAN dealer.
However, now and then you may notice
light spark knock for a short time while
accelerating or driving up hills. This is not a
cause for concern, because you get the
greatest fuel benefit when there is light
spark knock for a short time under heavy
engine load.
9-4Technical and consumer information
ZREVIEW COPY:Ð2003 Xterra(xtr)
Owners Manual(owners)ÐUSA English(nna)
02/24/03Ðtbrooks
X
ENGINE OIL AND OIL FILTER
RECOMMENDATION
Selecting the correct oil
It is essential to choose engine oil with the cor-
rect quality and viscosity to ensure satisfactory
engine life and performance. NISSAN recom-
mends the use of a low friction oil (energy con-
serving oil) in order to improve fuel economy and
conserve energy. Oils which do not have the
specified quality label should not be used as they
could cause engine damage.
Only those engine oils with the American Petro-
leum Institute (API) CERTIFICATION MARK onthe front of the container should be used. This
type of oil supersedes the existing API SG, SH, or
SJ and Energy Conserving II categories.
If you cannot find engine oil with the API CERTI-
FICATION MARK, use an API grade SG/SH,
Energy Conserving II or API grade SJ or SL,
Energy Conserving oil. An oil with a single desig-
nation SG or SH, or in combination with other
categories (for example, SG/CC or SG/CD) may
also be used if one with the API CERTIFICATION
MARK cannot be found. An ILSAC grade GF-II &
GF-III oil can also be used.NISSAN recommends mineral based oils. These
oils must, however, meet the API quality and SAE
viscosity ratings specified for your vehicle.
Oil additives
NISSAN does not recommend the use of oil
additives. The use of an oil additive is not neces-
sary when the proper oil type is used and main-
tenance intervals are followed.
Oil which may contain foreign matter or has been
previously used should not be used.
Oil viscosity
The engine oil viscosity or thickness changes
with temperature. Because of this, it is important
to select the engine oil viscosity based on the
temperatures at which the vehicle will be oper-
ated before the next oil change. The chart “Rec-
ommended SAE viscosity number” shows the
recommended oil viscosities for the expected
ambient temperatures. Choosing an oil viscosity
other than that recommended could cause seri-
ous engine damage.
Selecting the correct oil filter
Your new NISSAN vehicle is equipped with a
high-quality genuine NISSAN oil filter. When re-
placing, use a genuine NISSAN oil filter or its
equivalent for the reason described in “Change
intervals”.
WTI0033
Technical and consumer information9-5
ZREVIEW COPY:Ð2003 Xterra(xtr)
Owners Manual(owners)ÐUSA English(nna)
02/24/03Ðtbrooks
X