I don't buy this for a minute, in fact I know it to be untrue.

 

royal purple 240,000--------no problems

 

The Cummins NW here in town told me that synthetics where a wast of money. Now I don't if he is telling me that because he is miss informed or he mite know some thing. I ran conventional oil in my 1996 12 valve no problems. Personally I don't buy all the mumbo jumbo about oil additives. Slick50.engine restore,Z-MAX,Prolong I believe it's all snake-oil. Use a good conventional oil and change it every 3-5K and all is good. The synthetic rout cost way more per quart just so you can change your oil every 10K. I don't know. Just my 2 cents

 

Where I work we run 200 plus engines from 40hp up to 2000hp and the majority of them are Cummins, a few Cats. We run regular dino oil. Change it every 300 hrs or so and have very few oil related failures with our engines.

I have talked to our fleet mechanic about changing over to Amsoil as some of our units will burn 1200liters (317 gal) of fuel in a few hours. If the savings were truly there in reguards to fuel economy and cost then they would be using them. As stated by a few of the Synthetic companys even a 1% fuel increase would amount into a large fuel savings at the end of the year.

We also do cold starts, run our engines in extreme temps and also hard starts with full power to idle at short notice. If synthetic oil did provide a extreme advantage over dyno oil they would use them.

Regular Dyno is more then fine. The cost is right and the product works.

 

My two cents, I run dino in summer and synthetic in winter. The reason for synthetic is quicker oil pressure and faster engine cranking speed. After 10hrs parked while fishing with -25F to -35F temp you can tell the difference with synthetic. The test that convinced me to go full synthetic was the freezer test (or in my case outside test) ,viscosity pour.Dino oil of winter weight is like syrop in very cold weather while synthetic is much much easier to pour.Having said that, to pay double price for one oil change per year is cheaper than a bottom end of a cummins. Here in northwest ontario we can see cold snaps of -40F or -40C for a week at a time.

 

Well it's true depending on the sythetic oil you use because not all synthetic are true synthetics. Some are true PAO and some are mineral or oil based.
As others have said, why in the world would Cummins make a synthetic oil if yo could not run it in their engine

 

Synthetic oil is a very touchy and misleading subject. Synthetic can be used to describe how it is made as opposed to what it is made of. That is where many people think they are buying a oil from the next generation.
When in fact they are buying a highly refined petroleum product that may or may not have mineral oils as a main indgredient. (or it may be a mineral based with a petroleum added). Mineral = none petroleum product.

Will synthetic oil wreck your engine? No, will it prolong it's life maybe, maybe not.
Will conventional oil wreck your engine? nope, will it prolong it's life, maybe, maybe not.

That about sums it up.

 

10k? My Common rail manual that I got with the truck when I bought it says with my driving habits, I can go 15k on CONVENTIONAL motor oil before a change. I run Amsoil synthetic, and go 25k, with no issues at all... Oil analysis have all come back as ok to continue use, but I change it anyway, just because. I would never spend the $$ required to change the oil in my truck every 3-5k, even if I was using dino oil, that would add up REAL quick.

 

Dino oils are FAR better than just 10 years ago. So the "benefit" is less than before. And, as in the above posts, there is synthetic sorta, and synthetic for real. Price will usually tell you. MOBIL ONE DELVAC 5W-40 would be the default "true" synthetic.

I changed from dino to synthetic Rotella and found the engine turned over easier, even in hot South Texas. Good enough for me.

Cummins engines are easy on oil. EPA regulations have changed that somewhat (emissions devices), but the basic engine design makes this less important for us than some other brands.

 

As Hohn noted earlier, it is amazing to see the disinformation that still abounds. Wow...

Well, it is not just here or other diesel forums. On the Mercedes forum I visit, they'll argue about what weight of Mobil One will wreck the engine... 0/30 vs 5/40.

 

The oil sands plants in Alberta make synthentic crude NOT synthentic oil!
All that meens is they remove the coke and sulpher out of tar to make it close to regular crude oil.
I worked there for over 30 years!
The majority of it is sold for a higher price than normal crude to plastic producing companies etc because they dont have to decoke it to use in their manufacturing processes.
The best example of the use of real synthetic oil is out board or snowmobile use in engines running 8000 rpm on a 100 to 1 mix.
Try using your dino oil in one of them and see how far you get!!!
Case closed?

 

But the oil from the Oil Sands does end up making oil for our engines. Some of it even ends up being fuel. A few companies are labelling their oil and fuel as synthetic due to it comming from Non Conventional sources aka Oil Sands.

 

About the early 1990's I met a guy who we eventually became good friends. I was running a F150 and he had a Big Bronco. Both trucks had 351's in them and we both changed our oils `5000k miles. I used conventional oil, and he used synthetic.

I changed the valve cover gaskets on my truck from time to time, over the years I had owned the truck, and there was sludge accumulations in the valleys of the head. Since the truck was well maintained, or so I thought, I couldn't understand why there was so much gunk under those valve covers.

This friend of mine swore by Mobil 1 synthetic, and I thought he was crazy wasting his money on that "stuff". One day his valve cover gasket started leaking. This was @ about 150,000 miles. He wasn't mechanically inclined, other than changing his oil, so I offered to help him. I was absolutely shocked at the condition of the engine valvetrain, under that VCover. It was immaculate. There was little or no discoloration, nevermind any type of sediments / grime or goo. It looked as though he just put the heads on the truck.

I immediately switched to Synthetics, and I've used them ever since in all of my new vehicles. The fact that the synthetic oil left no deposits inside that engine sold me.

 

For my self the proof is in the UOA reports. I have yet to see Dino oil hold up as well as a real Synthetic oil like Royal Purple, Redline, Amsoil or even Mobil One. Its been proven many time that real synthetic oil will out last Dino oils, IIRC its twice as long. When I get my oil report its nice to see that the oil I threw out was still good for further usage that way I know my engine is getting some very good oil.