2004 Nissan Xterra Owner's Manual - Page 259

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 necessary when the proper oil type is used and maintenance intervals are followed. Oil which may contain foreign matter or has been previously used should not be used. Oil viscosity WTI0033 ENGINE OIL AND OIL FILTER RECOMMENDATION Selecting the correct oil It is essential to choose engine oil with the correct quality and viscosity to ensure satisfactory engine life and performance. NISSAN recommends the use of a low friction oil (energy conserving 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 Petroleum Institute (API) CERTIFICATION MARK on the 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 CERTIFICATION MARK, use API grade SG/SH, Energy Conserving I & II or API grade SJ or SL, Energy Conserving oil. An oil with a single designation 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-I, GF-II & GF-III oil can also be used. 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 operated before the next oil change. The chart "Recommended SAE viscosity number" shows the recommended oil viscosities for the expected ambient temperatures. Choosing an oil viscosity other than that recommended could cause serious engine damage. Selecting the correct oil filter Your new NISSAN vehicle is equipped with a high-quality genuine NISSAN oil filter. When replacing, use a genuine NISSAN oil filter or its equivalent for the reason described in "Change intervals". Technical and consumer information 9-5