05-07-2018, 06:23 AM
Diesel would dissolve(or rather suspend) most of the sticky deposits, that's for sure. But then, after draining the dirty diesel, there'll be more than a few ounces of diesel remaining in the sump and non-drainable areas, which will serve to dilute the fresh engine oil 
. Which is something we don't want. So methinks diesel treatment would(or could) do more harm than good.
An alternative would be what we used to do with marine engines in the past: After hot draining the oil, fill with SAE 10 or 30 and run for a few minutes, then drain and fill with fresh oil. But those were ancient diesels.
With today's modern engines and synthetic oils, I honestly don't think a little sludge at the bottom of the sump will not do any real harm. I'm sure Honda guys have thought about that
So I'm not splitting any hairs on the remaining oil in the sump. Drain warm, fill up, ride, check level
. Which is something we don't want. So methinks diesel treatment would(or could) do more harm than good. An alternative would be what we used to do with marine engines in the past: After hot draining the oil, fill with SAE 10 or 30 and run for a few minutes, then drain and fill with fresh oil. But those were ancient diesels.
With today's modern engines and synthetic oils, I honestly don't think a little sludge at the bottom of the sump will not do any real harm. I'm sure Honda guys have thought about that
So I'm not splitting any hairs on the remaining oil in the sump. Drain warm, fill up, ride, check level