I have a class A RV with a Cummings ISL 9, with 24,500 miles and 580 hours. I'm using Mobile Extreme full synthetic. The oil change interval by Cummings is 1000 hrs, 21,000 miles, or 18 months. Since my last oil change, I put on 6500 miles, and about 150 hrs, all extended highway miles. It has been sitting in the garage for the past year, except for occasional maintenance starts. Getting ready for another trip, but it's been 2.5 years since that oil change. Does oil go bad just sitting in the crankcase? Does it really need an oil change, just because of the 18 months?? Thank for your thoughts...
Diesel engine oil change interval
- Thread starter GKG
- Start date
I would change it. It may not need it but 2.5 years in that great engine, yes, I won't want to hurt the Cummins.
I would wager that oil is perfectly fine. I've done tests on our infrequently used diesel equipment and oil in those crankcases has been perfectly usable even at the 5 years mark. If it's stored properly and the Cummins doesn't suffer from high fuel dilution just run that oil out to the recommended OCI. Mobil Extreme is pretty stout as well.
BTW there's no G in Cummins.
Why cheap out? Extreme is $90 a pail. You've gotten your time/mileage out of this interval.
Fire it up and drive!
10000 to 12000 is safe to do as is with that kind of driving. Get an external bypass and just roll.
Thanks.. What is the external bypass. Is that a secondary filter that filters out smaller contaminants?
I think the main thing is testing your oil for moisture in the oil. If it's still acceptable then extend but I'd change by 10k or so.
I don't understand how folks miss this.
It appears you are unaware of that great engine manufacturer, Cummings, with a modern engine factory in Nigeria.
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Somalia.
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