Our "large dumps" (a mixture of tandem and single axle trucks) were changed at 10,000 mile intervals. A lot of the miles put on these trucks was plowing snow and, in summer time, a lot of hours idling on job sites.

While the truck was covered by warranty, new oil was used. As soon as the truck's warranty expired, they were switched to recycled oil. 

I worked for DOT for over 31 years and I don't recall ever seeing an engine wear out or ruined that could be blamed on the oil except we had a problem a few years back with oil pans rusting through (exposed to a lot of salt and calcium chloride throughout their life), until they went to composite oil pans.

I see a lot of people spending a lot of money on synthetic oil. These trucks didn't even get new oil!

Can you elaborate on the "frac fleet" machines please ??  40-50 GALLONS ?? , OUCH !!

Thanks Lars for the reply. Any idea of how many gallons of oil are in a LOCOMOTIVE ENGINE ??

DM, is it true that there ARE 2 stroke diesel engine on a locomotive ?? I recently did work in a home of a retired "CONRAIL" electrician that said that such an "animal" exists on the current rail lines .
 

Not only are they on rail lines, they're prevalent on rail lines.

The GM-EMD locomotive prime movers are super-turbocharged two-stroke.  The ones I taught on were four-valve head, full-authority electronically controlled fuel injected.

The super-turbochargers are, as it sounds, a two-function device.  A drive gear off the camshaft drives the compressor turbine through an overrunning clutch.  Once exhaust pressure rises sufficient to pick up the load, the exhaust turbine spools up, and exceeds the overrunning clutch, making it now a turbocharged engine.

They ARE two stroke, as the cylinders are ported for scavenging.  OTH I don't recall if it was set up for upflow (into port, exhaust out valves) or vise-versa,  I believe it was downflow, but I've taught too many others since then, but they were very well designed setups, and didn't discharge much lube oil under working conditions.

ALL engines, and Diesel engines in general, will discharge engine oil, as a result of running.  They do it most, however, when under little, or no load.  Why?  Because cylinder pressures are low, hence, pressure-based ring sealing force is nonexistant.  Once above 40% load, they are really tight.

The locos I taught on had a 500gal operating tank, with a 100gal feeder, they were designed to be maintained by the feeder.  Oil changes in those were spec'd at 6000 operating hours, but samples taken on a weekly basis, and the eductor system pressure tested at same time  as samples.  If a sample indicated a loss of quality or increase of some contaminant, it was responded to accordingly.

https://trains-and-locomotives.fandom.com/wiki/GE_7FDL_Engine" rel="nofollow - GE 7FDL Engine | Trains And Locomotives Wiki | Fandom

The EMD Four Stroke 1010 engine or H engine is current production line

https://en.wikipedia.org/wiki/EMD_1010" rel="nofollow - EMD 1010 - Wikipedia

The Two Stroke 567 and 645 engines were the mainstay for Generations of Rail Engines and Barge Tows.

https://model-railroad-hobbyist.com/node/33899" rel="nofollow - EMD 567, 567A, 567B, 567C, 567D, and Early 645 Test Beds | Model Railroad Hobbyist magazine (model-railroad-hobbyist.com)

I'm sorry, did I misunderstand something that was said earlier ? If so, I apologize to that poster 

Possibly,, he enjoys jumping on me like a few guys from ILL.; MO.; and the east coast though

I wouldn't jump on you if you were the last person on earth

But seriously......you talked to a RR employee that told you something, then you come on here and ask DMILLER if it is true?  WTF, so for some reason you didn't believe the guy who was a RR employee?  And you could have googled what you asked in mere seconds, rather than waiting for a reply. . . .from a guy from MO!

I used lots of emojis and typed real slow so you could understand.

The RR employee retired 31 years ago , seems like times "might" have changed   ! Have a happy Thanksgiving Tbone !!!