*A non-low ash oil meeting CES 20078 (API CI-4/SL) can be used with no change to the oil change interval, but will reduce the service interval of the Cummins Particulate Filter. Synthetic Oil May be used in ISL engine provided they meet performance and chemical requirements. CUMMINS ISL9-345 Engine for sale at Rock & Dirt Search from 1000's of listings for new & used CUMMINS ISL9-345 Engines updated daily from 100's of dealers & private sellers. Oct 12, 2017 · The Cummins ISL9 is used by medium duty trucks, RVs, motorhomes, fire trucks, emergency vehicles, and much more.