Change you oil and filter on a regular basis, use a diesel spec'ed oil and you need nothing else.
Not really so. Case in point.
I had two identical european diesels, one had 60k miles on a rebuild , had been run on synthetic since the rebuild and maintained religiously. I had to tear it down after a stuck thermostat issue forced a rebuild, and even with that kind of detergent cleaning, I had to spend the usual amount of time with the ring groove cleaner on each piston cleaning out all the soot and varnish out of the ring grooves
( with my arthritis, that meant about a week to get the pistons cleaned up ). The engine had begun to exhibit signs of some oil consumption ( obviously due to sticky rings after seeing the ring grooves and the buildup in the oil control rings)
The second engine had well over 250k miles on it, had been thoroughly neglected and was inhaling a qt of oil every 30 miles when I aquired it. Ran a few Auto Rx treatments and oil consumption went to well over 800 miles on a qt ( within acceptable range spec ) . A while later I had to tear that engine down due to an unrelated issue and use of the ring groove cleaner was not needed, I was ablle to clean up the pistons and rings with a spray can of brake parts cleaner!
So really, any old diesel could benefit from a good cleaning once in a while. You've got to remember, over the road tractors have ALL run bypass oil filters for decades which helps tremendously in their ability to fend off the soot issues.