Cummins ISX15 Engine Oil
CES 20086 / CES 20081 Spec, Viscosity & Drain Intervals
ISX15 Oil Specification
- The ISX15 is the predecessor to the X15 — same basic architecture, different emissions tier
- EPA10 ISX15 engines (2010–2016): CES 20081 required — CI-4+ / CJ-4 equivalent
- CES 20086 oil used in a CES 20081 engine: no issue — 20086 is backward compatible
- X15 (2017+) uses CES 20086 exclusively
- FA-4 is not approved for the ISX15 Not Approved — use CK-4 15W-40
- Drain intervals: 15,000–25,000 miles depending on application and oil quality
AMSOIL Products for the ISX15
Frequently Asked Questions
What oil does the Cummins ISX15 take?
CES 20081 (EPA10 era) or CES 20086 (current). 15W-40 CK-4 is the primary grade. FA-4 is not approved for the ISX15.
What’s the difference between CES 20081 and CES 20086?
CES 20081 was Cummins’ specification for CI-4+ and CJ-4 era oils. CES 20086 is the current spec for CK-4 era oils introduced with GHG17. CES 20086 oil can be used in CES 20081 engines — it meets and exceeds the older standard.
Is the ISX15 the same engine as the X15?
They share architecture but are different emissions platforms. The ISX15 covers 2010–2016 EPA10 production. The X15 replaced it in 2017 for GHG17. The X15 uses CES 20086 exclusively.
Can I use AMSOIL in a Cummins ISX15?
Yes. AMSOIL Signature Series Max-Duty (DME) and Heavy-Duty (ADP) both carry CES 20086 approval, which satisfies CES 20081 requirements in ISX15 applications.