How many miles do you run before you change your oil?

I switched to long life oil and now I change every 20 K miles

 

what is long life oil ?

 

I change my oil and fuel filters at 15,000

 

15,000 miles

 

I guess my first question would be, why not start at the OEM recommended interval, figure out how things look, and adjust from there? There is not a motor that I know of for the last 10 years that the OEM has recommended anything less than 25,000 miles / 500 hrs, except in the most harsh operations. Even Cat with the C-15 and Acert states clearly in the lube manuals that as long as the motor is not getting less than 6 mpg average, 25,000 miles / 500 hrs is the recommended interval. (if you are averaging less than 6 mpg all the time doing general freight, you have issues bigger than when to change your oil). Same for Cummins, Mack, Volvo, Maxxforce, Detroit 60, etc. Some of these recommend even longer, with Detroit DD15 the longevity winner by far, at least OEM recommended interval. Whether that works out in the real world, that is what oil analysis is for.

The same thing goes on with personal vehicles. Folks got stuck on the 3000 mile interval for so many years, but it is well known that modern oils can easily be run to a minimum of twice that and sometime 3 times that. I know changing oil frequently "feels" better, but it sure makes one's wallet lighter.

I have not done one oil change since 1992 less than 20,000 miles (except first oil change usually at 10,000), many even longer. My starting point has always been the OEM recommended drain interval. One motor, a 1996 Cummins N-14 got 30,000 mile oil changes over it's entire life with only one injector and an accessory drive seal needing repair. Got sold at 1.4 million and went right to work for a farmer. All it got was Kendall 15w40 conventional, Baldwin filters. No bypass filter, no snake oil additives, no "long life" oil, whatever that is.

 

heavyhaulerss: I question that also and work with a company that runs 8000 series John Deere's. With tractors at 7-10,000 hours they decided to go from 250 to 500 hour services using JD Plus 50 II oil and JD filters. I could not read on a jug what it is but it is not a full synthetic or it would not say, on line, that it is compatible with full synthetic oil. I have been told it is a synthetic blend. A company my company services trucks for has C15's They go 25,000, never ask what kind of oil is used, and want Cat filters used. If the new oil and filters are up to these extended intervals that's great but did you know these oils have transient qualities? Now there is no need to grease, inspect, or adjust anything for the same time period. I do not want one when they are done with it.

 

We are discussing motor oil. While some fleets and such will only grease at oil change time, many of us are a little more frequent than that. Even the fleet I am contracted with, they do their company truck greasings and general inspections every 8,000 miles.

 

20,000

 

Depends on motor. DD15 is 50,000, Cummins ISX is 30K for less than 6.5 mpg or 40K for higher, Volvo D13 is 35,000 miles, Maxxforce 13 is 40,000 miles. There is not a heavy diesel engine made, as used in typical OTR general freight, that the OEM recommends less than 25,000 mile oil changes. Severe service rock hauling or heavy hauling may be different.

Oh, just found all this info readily online at each OEM website. Love how some will speculate what should be done and have no clue what the folks who build the motor have to say on the matter.

 

Yes cummins manual says change oil depending on fuel mileage. If its more than 6mpg 40000miles. But do you thing they test engine before they sell it to market? These days firs they sell and wait results from us.
Today I looked at my friends oil sample. He had 40000miles with bypass filter. Soot level 3.5%. You thing its ok such big oil drain intervals??