MF 135 owner's manual, type of oil, and options?

The only reason they used it back then was because detergent oils hadn't been developed. Detergent oils are far superior at suspending dirt and getting it out of your engine. If your engine has not had detergent oil in it for a long time, it would be a good idea to change the oil and filter at short intervals for the next few times.

Before detergent oil was available, I remember using "coal oil" (you'd have to use diesel today) as an engine flush to get the crud out. After draining the old oil out and before changing the filter, I would dump a gallon of coal oil in the crankcase and run the engine for about a minute. Flushing the lighter oil through the lines would give it a good rinsing and kept sludge from building up in the pan.

When detergent oil became standard, that practice died fast.

As to the oil, I would use detergent oil. HOWEVER- if it is really dirty inside this may not be a good idea. The detergent may break the crud loose, and cause problems. If you decide to use regular oil, I would change it and the filter often.

Other opinions??

Good luck,

Bob