Garden tractor engines are made to propel both the lawn mower and turn the blades. They are classified as small engines and are rated anywhere between 5 and 25 horsepower. They are all internal combustion engines, and they all need motor oil to run properly. However, each manufacturer has its own specifications for what type of motor oil should be used in its particular engine. Although there are no hard and fast rules as to which oil is best for any given garden tractor engine, there is one type of oil that can be used in all of them.
Use straight 30-weight oil for operation between temperatures of 32 and 104 degrees Fahrenheit. This motor oil is acceptable in all garden lawn tractors.
You should use a multi-viscosity oil for climates with major temperature variations. A 10W30-weight oil is the equal or better of a straight 30 weight oil and will be most beneficial for northern climates. However, other multi-viscosity ratings of 5W30 or 10W40 can also be used in most instances.
Run "Arctic oil" in a garden tractor engine when using it in sub-zero climates. This is a 0W30 motor oil that is only to be used when the ambient temperature does not exceed 15 degrees Fahrenheit.