I bet that "diesel expert" would soil himself if he found out how diesel engines are treated in the terminal tractors at UPS. 100+ starts and stops a day per shift, floored right from cold start to build air, shut off while the engine is still decelerating a lot. Those things barely get an oil change, 3 maybe 4 times a year, which depending on how much one particular rig is used can be close to 700-800 hours of run time between oil changes. Never an engine problem out of those things, always something else. One ISB 5.9 had 40,000 hours on it when it was retired. That truck was beyond worn out junk, but the engine still ran great. I don't know what kind of oil is in the bulk tank in the shop, but it's most likely the cheap stuff knowing that company. I have seen 55-gallon drums of Mobil Delvac 1300 10w30 in the shop at times, so good chance it's that. Another thing that gets me are the people that let their diesel sit there and idle for a while before shutting them off like it will make a difference. Not sure how many thousands of times I've shut one of those down off idle and still heard the turbo spooling down after the engine stops rotating, but it's a lot. Just my experience of trying to beat the rods out of those diesels for a living.