A little more explanation on oil. You must look far and wide to find a multi viscosity oil without detergent as a component. Virtually all modern multi-weight oils are detergent oils. You do not need to buy a diesel rated motor oil to get detergent.
Neither do you need to buy the diesel tractor oil such as Walmart sells at $4.95 a quart.
Short answers, imcluding mine, do not do justice to most subjects. Manuals are also somtimes misleading. A 22 or 25 year old tractor has the same year engine and the same year manual. Multi viscosity and detergent oils have come about in the last 20 years and so are not mentioned in the manuals before then. They only had single 20,30,40,50, etc. and so that was what was recommended.
Japanese fuels are low sulphur. Canadian and U.S. are high sulphur and Europe is in between. (Sorry, don't know about Australia, etc. ) North America has a much greater need for detergent than elsewhere.
The following are both gasoline and diesel motor oils and are typically sold as motor oil. Carquest Fleet Motor Oil, Castrol Heavt Duty, Valvoline All Fleet, (Chevron) Delo 400 Heavy Duty, and Napa Universal Fleet, to name a few.
All have the following features: "Are ideal for naturally aspirated and supercharged diesels. For use in high output gasoline and diesel engines. Exceeds the manufacturers' specifications; Cummins, Mack EO-M, Detroit Diesel (4 stroke), Caterpillar, Navistar, Allison C-4,
and Caterpillar CD/TO-2."
Hope this adds some clarity.
Here is a good web site
<a href="http://www.nordicgroup.us/oil.htm">