Last two changes, really unneeded but done at same time as engine oil change etc was with Royal Purple oil full real synthetic.
I'm having a hard time filtering through the advertising and so put out about the different oils. The dyno synthetics such as most Mobile One and Catol and so on are just dyno oil more refined. Red Line is full ester based synthetic as are a number of European spec oils for Porsche and so on.
Some posted a link and sources for a number of real full synthetics some time ago. The Royal Purple in the generator, well, the filter when changed was not very dirty neither was the oil something not accustomed to in any diesel. And it is slicker than snail snot.
One week, I will sit down and try to find a real comparison chart and tests and not puffing and false claims by Oil companies.