I worked for a company that ran a fleet of coal haul trucks with cat 3512 engine in them and upon overhaul, they would set some up on synthetic, and some on dino oil, and did fairly meticulous sampling, and records keeping. Engine life was pretty much the same across the broad with much higher cost for the synthetic(those engines held 18 gallons if I remember right) as others here have said its, all about keeping the oil clean. Proper viscosity is also paramount, those engines had a prelube system so those the engine had oil pressure before it even started turning, but if you run the wrong wieght of oil you can also cause alot of wear on start up, as start up has been proven to be the time when any engine is most prone to wear. Thats my 2 bits
Coleman Barnett
Absarokee,Montana
