Mercedes OM471 Engine Oil
Quick Spec Reference
| Engine | Mercedes-Benz OM471 |
| Displacement | 12.8L Inline-6 |
| Vehicles | Freightliner Cascadia (2018+), Western Star models |
| Primary Spec | MB 228.51 (5W-30 FA-4 — preferred) |
| FA-4 Grade | 5W-30 FA-4 — approved |
| CK-4 Grade | 15W-40 CK-4 (MB 228.31) |
| Capacity | 42 qt / 10.5 gal (with filter) |
| OEM Drain | 25,000 mi (highway) · 15,000 mi (severe) |
MB 228.51 vs MB 228.31 — Which Spec Do You Need?
Mercedes-Benz publishes two primary oil specs for heavy-duty diesel applications. The OM471 in North American Freightliner Cascadia trucks approves both — but they’re not interchangeable.
MB 228.51
- Grade: 5W-30 FA-4
- Focus: Fuel efficiency + low viscosity
- API: FA-4 approved
- Best for: 2018+ Freightliner Cascadia, highway fleets
- Advantage: Up to 1.5% better fuel economy vs. 15W-40
MB 228.31
- Grade: 15W-40 CK-4
- Focus: Heavy-duty protection, wider temp range
- API: CK-4
- Best for: Older fleets, severe duty, mixed-fleet shops
- Advantage: Broader availability, proven track record
For 2018+ Cascadia operators running the OM471, MB 228.51 with 5W-30 FA-4 is the factory preference. If you’re topping off or running a mixed fleet on 15W-40, use a CK-4 product that meets MB 228.31 and you’re still in spec.
Viscosity Grades for the OM471
Two grades are OEM-approved. Which one you run comes down to your spec, climate, and whether your fleet is chasing fuel economy.
Factory-preferred for 2018+ Cascadia OM471. Meets MB 228.51. Lower viscosity = measurable fuel savings on highway miles. Cold-start performance is better than 15W-40. Full synthetic only.
OEM-approved under MB 228.31. Wider viscosity range — reliable in hot or demanding conditions. Common in shops running mixed fleets. Use a product explicitly approved to MB 228.31.
OEM Drain Intervals — OM471
Mercedes-Benz publishes two OEM intervals for the OM471 based on operating conditions. These apply to oils meeting the respective spec. Exceeding them without oil analysis is not recommended.
Standard OEM interval for over-the-road highway operation with MB 228.51 or MB 228.31 approved oil. Applies when operating conditions are normal, no excessive idling or stop-and-go.
Applies in severe conditions: heavy stop-and-go, PTO operation, extended idling, extreme temperatures, or vocational/construction applications. Drop to 15K mi to stay protected.
Recommended Oil for the Mercedes OM471
Both products below are spec-appropriate for the OM471. The 5W-30 FA-4 is the first pick for fuel economy and MB 228.51 compliance. The 15W-40 CK-4 covers MB 228.31 for operators who prefer or require a heavier grade.
AMSOIL Signature Series Max-Duty 5W-30 (FA-4)
Top-tier FA-4 full synthetic formulated for modern low-emission diesels. Meets MB 228.51. Fuel efficiency gains on highway hauls, superior cold-start protection, extended drain capability with oil analysis. 42 qt fill for the OM471.
AMSOIL Signature Series Max-Duty 15W-40 (DME)
Full synthetic CK-4 meeting MB 228.31. Built for severe heavy-duty operation — high temperatures, heavy loads, extended drain potential. Right choice for mixed fleets or operators preferring 15W-40 viscosity.
Frequently Asked Questions
The Mercedes OM471 requires oil meeting MB 228.51 (5W-30 FA-4, preferred for fuel efficiency) or MB 228.31 (15W-40 CK-4, standard heavy-duty). For 2018+ Freightliner Cascadia trucks, 5W-30 FA-4 meeting MB 228.51 is the factory-preferred grade. Capacity is 42 qt (10.5 gal) with filter.
MB 228.51 is a Mercedes-Benz factory oil specification for fuel-efficient heavy-duty diesel operation. It requires FA-4 viscosity-grade oils — typically 5W-30 — meeting strict low-viscosity and shear-stability standards. It’s approved for the OM471 engine in Freightliner Cascadia and delivers measurable fuel economy improvements over the older MB 228.31 spec.
Yes — 15W-40 CK-4 is acceptable in the OM471 when it meets the MB 228.31 specification. The preferred modern grade is 5W-30 FA-4 (MB 228.51) for fuel efficiency. If you run 15W-40, use a product explicitly approved to MB 228.31. Do not use generic FA-4 oil in engines that haven’t approved it — FA-4 is not backward-compatible with all heavy-duty diesels.
The Mercedes OM471 holds 42 quarts (10.5 gallons) of engine oil with filter change. Always verify your specific configuration — remote filters or auxiliary oil systems can affect total capacity. Check the dipstick after fill and allow the engine to fully warm up before final verification.
Freightliner Cascadia trucks equipped with the Mercedes-Benz OM471 use 5W-30 FA-4 meeting MB 228.51 (preferred) or 15W-40 CK-4 meeting MB 228.31. The 2018+ Cascadia with the OM471 is approved for FA-4, which improves fuel economy on highway hauls. OEM drain interval: 25,000 miles (highway) or 15,000 miles (severe service).
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