Dino oil or Synthetic in motor?

[BruteForce]

I use Valvoline Blue 15w40 in my Cummins 6.7l CTD and change every ~5k miles. I get an oil analysis every other oil change and the reports are favorable. At the end of the day, it boils down to costs -v- frequency of oil change.

I buy 3 gals of oil at $10/gal + $12 oil filter and my time to change oil, plus return a bucket of used oil to an auto parts store.

If you use synthetic, you get around 3x more life from your oil and maybe more if you have after market oil filtration and EGR/DPF deletes in place.

I think it just boils down to personal preference. Synthetic is expensive, but you get more use (time) out of it.

 

[porthole]

Dilution shouldn't be an issue in the '11 Duramax's as the DPF Regen is accomplished by a ninth fuel injector in the exhaust system ahead of the DPF. They also go about twice the distance between regeneration thanks to the Diesel Exhaust Fluid.

Fuel dilution in the oil is a possibility with any internal combustion engine.

We just hear about it more with diesels because of the higher pressures involved.

I leaky injector in either of the Hi-Po 2011 diesels will dilute the oil with fuel.
And diesels don't like diesel in their crankcase.