John Deere riding mowers have gasoline-powered engines and are intended for residential mowing. The company refers to its larger mowers -- which may be used for residential or commercial applications -- as lawn tractors. These units have either gasoline or diesel engines. John Deere recommends consulting your riding mower owner's manual for the exact type of recommended oil. A knowledge of oil viscosity can help guide you, however.
Recommended Oil Viscosity Grades
John Deere prefers that 10W-30 be used in all its gasoline-powered engines, including those on riding mowers. The "W" indicates that the oil was tested at low air temperatures. A 10W-30 weight engine oil is viscous even at temperatures as low as negative 4 degrees Fahrenheit. For climates where temperatures do not plunge below zero, John Deere says that 15W-40 oil "provides the best engine performance and protection" for temperatures that do not go below 5 degrees Fahrenheit. For those people living in colder climates, 5W-30 oil works well in weather between negative 22 degrees and 104 degrees Fahrenheit.
John Deere Oils
John Deere recommends the use of its own brands of engine oil. The company explains that its oils have additives and performance enhancers that reduce corrosion and keep internal engine parts running cleaner. Other brands of engine oil will also work well provided they prevent sludge, resist foaming and perform within the indicated temperature ranges in addition to reducing corrosion while cooling and lubricating internal engine parts.