Marin says:
"But his involvement with the Lehman engines is far more than just as a mechanic." Yea.....he's a small business man. I know you guys like uncle Bob but I think his opinions are too close to opinions. I'd go w the manual. And multi-weight oil is like "premium" gasoline. It's only needed if it's needed. Otherwise you're just buying hype and wasting your money.
But when it's needed and in some applications...like running my truck in the winter...it's needed regularly... Plus the guy was a VP with Ford for the Lehman division...probably reviewed the manuals more than once or twice....guess that doesn't account for much.
Mark...No but ""Engineered for pre-2007 diesel engines in on-road applications as well as all model year diesel engines in off-road applications." would be 98% of a green flag to me but then I do'nt see any reason to use it. Being an experimenter I'd be inclined to try it re what psneeld said. Those boatDiesel guys are onto that diesel stuff but I'll bet there's still some old wife's tales and off the mark opinions. Very high level of experience and knowledge though. Like Bob Smith........opinions but good opinions.... for serious considerations but not the last word. Even what engineers say is questionable ...but far less so.
Multi-vis fine. Syn oil fine ...if it's for a diesel engine but again there's no downside for using 30W dino. And one can use the money saved to do more frequent oil changes and that definitely is better for the engine.
More frequently to a point...then it's a waste of money like you mentioned in para 1
Psneeld, .....Some time back it was said that multi-vis oils were fine when new but lost some or most of their multi-vis performance so 15W40 would soon become 20W oil or 15W. I think the base oil for say 5W30 oil is 5W oil.
I'm sure they lose some of their properties over time/usage...but the multis are being run in tractor trailers for many more miles than our 200 hour intervals because they go with oil analysis..so the multi rating isn't given up too easily...
Any of the this correct?