Originally Posted by neil64
My Walmart had Delo 400 15w-40 CJ-4 for $8.50/gallon last night. I have never used it before but this is the truck's first oil change (2800 miles) so I want to put dino back in until the rings seat, whenever that is. I couldn't resist the price given its reputation.
Delo - Engine Oils
"Dino" oil is not going to seat your rings any faster than synthetic motor oil.
The only advantage synthetic motor oil has is the ability to produce a flatter viscosity curve vs temperature. 5W40 is practical with fewer viscosity improvers. Viscosity improvers are weak and do not last as long as the base oil, so having fewer means the oil stays within the viscosity specification longer. That is most of the basis for extended drain claims for synthetic.
15W40 is the standard for refined Diesel motor oil as it can be produced with minimal viscosity improvers which results in a longer life by staying within viscosity spec.
There are thousands of fleet managers monitoring diesel engine wear. If synthetic motor oil reduced more wear than its added cost then refined motor oil would immediately be past history. Same goes for extended drain, if it cost twice as much but went twice as long then it might be accepted. Synthetic vs refined is not a religion for fleet managers, but operating cost is.