re: Ram 1500 ecodiesel

ULSD has other additives to make up the lubricity for the fuel system. Unless you have major washdown then that shouldn't be the issue. I would expect it might be the oil shearing down from the high pressure drive of the fuel system but a full synthetic diesel oil shouldn't have that issue considering it isn't an issue with domestic turbo diesels already running high pressure oil to drive fuel injection. CTD has a 15k OCI with 12qts of conventional diesel oil. You can pull the oil pan on any current diesel that has been properly serviced with hundreds of thousands of miles on the bottom end and you will virtually zero varnish that comes from fuel byproducts you'd see in a gas engine. Modern HDEO's are damned good so I would hope there is a good reason for a 10k OCI.