dart4forte

Changed at 3K, no problem other than black oil

HOHN

I switched mine at 12K.

No negative issues at all-- no oil consumption problems, no low MPG or anything.

I've also switched back to dino, and back again to syn. NO problems.

I've mixed syn and dino. I've mixed 15W-40 and 10W-30. NO problems. Consumption remains normal-- which is to say that it doesn't seem to burn a drop between changes.


Cummins says 20K and there's nothing wrong with that, but I think it's a little cautious. Engine break-in is a logarithmic function, and 20K isn't much different than 10K.

TurboTed

I think we're on the same track. Let's say the oil is made by the same company. 0W40, 5W40, 10W40, and 15W40 should all be the same viscosity at 100 degrees Celsius. Obviously the 0W40 will be less viscous at say -30 Celsius. I am not sure whether it will be less viscous than the others when you start up at +20 celsius in the summer. However, you can use synthetics such as Esso 0W40, or Dello 5W40 for easier starts in the colder months. So- what's important I guess, is that all the oils with a 40 weight will only thin out a certain amount at a really hot (say 100 Celsius) temperature. I suppose there are other 30 weight oils made by another manufacturer that will stay as viscous at those temps.??

preloader

Changed to Amsoil 15-w40HD at 20k, now running a less expensive syn., Rottela-T 5w-40. No problems

Hounddog

Differance in price is also the differance between a Group 4 full synthetic and a Group Three dino oil thats caled synthetic and just been cooked a lttle better and longer then standered oil.You get what you pay for.

DieselBD

I saw it at Autozone.

I just changed my oil to Rotella synthetic, 40k miles, no leaks,