Synthetic oil

I have always run Mobil 1 synthetic because synthetics do not lose there viscosity. When you drain it out 5000 miles later it's still 10w-30 where as dino oil will lose it's viscosity because of heat and 5000 miles later is almost useless.
Remember with out synthetic oil there would not be jet engines.
To me it's a small price to pay to keep the truck protected.

Cummins12V98 wrote:

The Mad Norsky wrote:

AH64ID wrote:
The Diesel engines built since Jan 1 2007 are not capable of extended oil drain intervals with their emissions intact.

:h


Hmmmm?

My new Cummins Ram says to go 15,000 miles before oil change.

Mind you, I am NOT wild about that idea. Especially considering they tell me it is just normal old Rotella 15W/40 in the crankcase.

New Cummins come with Synthetic oil.

I wish I knew for sure. I just bought a "new Cummins" and was informed by the service manager at Dave Smith Motors that it was Rotella 15W/40 in my engine.

Not Valvoline (as I expected) nor synthetic.

I think the only folks who really know are those at the factory where the Cummins engines are assembled.

Sometimes I do think service managers are on the bottom of the list when it comes to things to know about your vehicle.

wintersun wrote:


Most synthetics for diesel are not available in a 15W-40 grade which is also what is needed for temperatures above 0 degrees. A 5W-40 oil in temperatures above 0 degrees is not going to provide nearly as good protection in warmer temperatures. One is already sacrificing lubrication performance with a multi-grade oil with polymer shear which is most evident when oil is forced into the main bearing journals of an engine.

You might want to do some research on oil viscosity.

GoPackGo wrote:
I think if everyone could see oil temps while towing, there would be more people running synthetic oil.

Why? When is the last time you have seen a blown up engine due to oil problems?

Question: How many of you have worn out an engine in your TV?

Again, here is another thread with some seriously wrong info.

If you want to know the truth about motor oil, this is NOT the forum to find it.

GoPackGo wrote:
I think if everyone could see oil temps while towing, there would be more people running synthetic oil.

Not just the extreme heat, but also how much better synthetics flow in the extreme cold. The extra cost of full synthetic oil is insignificant when you consider the extra benefits they provide.

I think if everyone could see oil temps while towing, there would be more people running synthetic oil.

GoPackGo wrote:
I saw 245 degrees oil temperature when towing my 5th wheel on those long uphills in the Rockies this summer. It normally runs about 205 degrees on the flats.

I run full synthetic oil.

That's why I use it down here in Florida and around the southeast where heat is a consideration. Just incase the oil reaches 300*F in the journals or wrist pins or even the valve guides while towing our 5th wheel in the heat of summer. Probably doesn't but, I sleep better knowing it's in there just incase it does.

I saw 245 degrees oil temperature when towing my 5th wheel on those long uphills in the Rockies this summer. Do you really want to run dino oil in that situation. I think not. It normally runs about 205 degrees on the flats.

Rotella makes a 15w40 full synthetic.

My 2013 Ford owner's manual diesel supplement states 5w40 is to be used for severe duty situations between temps of -20 and 100+ degrees. Since it's their engine and I figure they might know what's best for it, I run Ford full synthetic 5w40 oil.

Ford recommends 15w40 only down to 20 degrees for my engine.