Detroit Diesel DD15 — 14.8L Inline-6
Detroit DD15 Engine Oil — Spec, Capacity & Change Interval
The Detroit DD15 is Detroit's 14.8L heavy-duty engine, found in Freightliner Cascadia and Western Star trucks. Most DD15 oil confusion comes from two Detroit specs: DFS 93K222 (API CK-4) and DFS 93K223 (API FA-4). Every DD15 can run 93K222. EPA10 and newer DD15s can also run 93K223. Get the spec right, buy the right quantity, and run Detroit's interval for your duty cycle.
Last reviewed: October 2026 · Based on Detroit Diesel (DTNA) service literature and AMSOIL data sheet G3467
A Detroit DD15 oil and filter change takes 45 quarts (43 L, about 11.25 US gallons). Every DD15 can use oil meeting DFS 93K222 (API CK-4); EPA10, GHG14 and GHG17 DD15s may also use DFS 93K223 (API FA-4). Detroit's oil change interval runs from 35,000 mi in severe service to 75,000 mi in efficient long haul. My pick for every DD15: AMSOIL Max-Duty 15W-40 (DME).
Change
Inline-6
Every DD15
Efficient Long Haul
DD15 Oil Spec by Generation — EPA07 vs EPA10 and Newer
Detroit splits DD15 oil by emissions generation, not by 2017. EPA07 DD15s must use DFS 93K222 (CK-4). EPA10, GHG14 and GHG17 DD15s can use either DFS 93K222 (CK-4) or DFS 93K223 (FA-4). Check your emissions decal before buying oil, then pick the spec your fleet stocks.
- Oil SpecAPI CK-4
- Detroit SpecDFS 93K222
- Primary Viscosity15W-40
- Cold Climate5W-40
- FA-4 Allowed?No — 93K222 (CK-4) only
- AMSOIL ProductDME 15W-40 / DEO 5W-40
- CK-4 SpecDFS 93K222
- FA-4 SpecDFS 93K223
- Which to Run?Either is approved
- Detroit Preference93K223 for fuel economy
- CK-4 Acceptable?Yes — fully approved
- AMSOIL ProductDME 15W-40 / DHD 5W-30
How to identify your DD15 generation: Check the emissions certification label on the engine or door jamb. It shows EPA07, EPA10, GHG14 or GHG17. If in doubt, call Detroit Customer Support with your Engine Serial Number.
⚠ Do not use FA-4 in an EPA07 DD15. Detroit limits EPA07 engines to DFS 93K222 (CK-4). FA-4's lower high-temperature high-shear (HTHS) viscosity is only approved on EPA10 and newer DD15s.
Detroit DD15 Oil Capacity
A DD15 takes 45 quarts (43 L) at an oil and filter change, per Detroit's own capacity tables. Total dry volume after a rebuild is 51.8 quarts (49 L), because about 6 litres stays in the engine at a normal drain. The DD16 takes the same 45 quarts. Older guides that list the DD15 at 36 or 47 quarts are wrong.
| Fill Type | Quarts | Litres | Gallons | Notes |
|---|---|---|---|---|
| Oil & Filter Change | 45 qt | 43 L | 11.25 gal | Standard oil change |
| Total Dry Volume | 51.8 qt | 49 L | 12.9 gal | New engine or rebuild |
| DD16 Oil & Filter Change | 45 qt | 43 L | 11.25 gal | Same as the DD15 |
⚠ Always verify capacity with your engine's service label. Overfilling causes oil foaming, aeration, and seal damage. Underfilling reduces oil pressure margin under high load.
Buy the Right Oil for a DD15 Service
A DD15 oil and filter change takes 45 quarts, about 11.25 US gallons. Two AMSOIL Twin Packs plus two gallon jugs is 12 gallons: one full service with 3 quarts left for top-offs. For fleets, a 275-gallon tote covers 24 DD15 services.
- Meets the requirements of DFS 93K222
- One service: 2 Twin Packs (DMETP-CA) + 2 gallon jugs (DME1G-EA) = 12 gal
- The oil I recommend for every DD15
- Meets the requirements of DFS 93K222
- One service: 2 Twin Packs (DHDTP-CA) + 2 gallon jugs (DHD1G-EA) = 12 gal
- One oil for mixed fleets and cold starts
- One truck under your own authority qualifies
- Lower cost per service than jugs
- One 275-gallon tote covers 24 DD15 services
- Shipped direct to your shop or yard
Run Detroit's interval for your duty cycle (up to 75,000 mi in efficient long haul). Want to go past it? Do it on oil analysis, not guesswork. Get an Oil Analysis Kit →
DD15 Oil Change Interval
Detroit sets the DD15 oil and filter interval by service category, on DFS 93K222 or 93K223 oil: 75,000 mi in efficient long haul (7.0+ mpg), 60,000 mi in long haul (6.0–6.9 mpg), 45,000 mi or 1,000 hours in short haul (5.1–5.9 mpg), and 35,000 mi or 750 hours in severe service (up to 5.0 mpg).
(121,000 km)
(97,000 km)
(72,000 km) or 1,000 hr
(56,000 km) or 750 hr
⚠ Going past Detroit's interval? Do it on oil analysis. On modern DD15s, Detroit's own intervals already reach 60,000–75,000 mi. A good synthetic gives you more margin inside that interval. Going beyond it safely takes a lab report on your own truck, because high idle time, biodiesel blends, EGR cooler leaks and soot loading all shorten oil life.
FA-4 vs CK-4 on the DD15
Both are approved on EPA10 and newer DD15s. DFS 93K222 is Detroit's CK-4 spec (minimum HTHS 3.7 cP) and covers every DD15. DFS 93K223 is Detroit's FA-4 spec (minimum HTHS 2.9 cP) for EPA10, GHG14 and GHG17 engines, where Detroit recommends it for fuel economy.
FA-4 — DFS 93K223
- ✓ Approved for EPA10, GHG14 and GHG17 DD15s
- ✓ Lower HTHS viscosity for fuel economy
- ✓ Detroit's recommended spec on EPA10 and newer
- ✗ Not approved for EPA07 DD15s
CK-4 — DFS 93K222
- ✓ Approved for every DD15, EPA07 through GHG17
- ✓ Higher HTHS viscosity, more film strength
- ✓ One spec for mixed-generation fleets
- → May give up a little fuel economy vs FA-4
Simple rule: DFS 93K222 (CK-4) works in every DD15. DFS 93K223 (FA-4) is approved on EPA10 and newer, but never in an EPA07 engine. Note: AMSOIL's heavy-duty diesel oils are CK-4 oils that meet DFS 93K222; AMSOIL does not currently offer a 93K223 FA-4 oil.
What Is DFS 93K222?
DFS 93K222 is Detroit Diesel's engine oil specification built on API CK-4, with a minimum HTHS viscosity of 3.7 cP. It adds Detroit's own testing on top of the API category, including a DD13 liner scuffing test, and covers every DD13, DD15 and DD16 from EPA07 onward.
Shear Stability
Oil must retain viscosity under heavy mechanical shear.
Soot Handling
Oil must keep soot suspended and prevent larger wear-causing particles.
Aeration Control
Oil must resist air entrainment that reduces film strength.
Liner Scuffing
Detroit's scuffing test directly measures cylinder liner protection.
| Spec | Applies To | API Equivalent | Viscosity |
|---|---|---|---|
| DFS 93K222 | Every DD13 / DD15 / DD16, EPA07 onward | API CK-4 · HTHS ≥ 3.7 cP | 15W-40, 10W-30, 5W-30, 5W-40 |
| DFS 93K223 | EPA10 / GHG14 / GHG17 only | API FA-4 · HTHS ≥ 2.9 cP | Low-viscosity FA-4 grades |
| DFS 93K218 | Older CJ-4-era spec | API CJ-4 | Superseded by 93K222 |
Best AMSOIL Oil for the Detroit DD15
For every DD15, I recommend AMSOIL Signature Series Max-Duty 15W-40 (DME), a CK-4 oil that meets the requirements of DFS 93K222. Max-Duty 5W-30 (DHD) is the fuel-economy and mixed-fleet option, and Max-Duty 5W-40 (DEO) is the cold-climate pick.
- Meets the requirements of DFS 93K222
- Approved spec for EPA07 through GHG17
- 6X more wear protection than Detroit's DD13 scuffing test requires
- Strong hot-temperature film protection (HTHS 4.5)
- Meets the requirements of DFS 93K222
- Lower viscosity for GHG17 fuel economy
- Also lists Cummins CES 20086, Mack EOS-4.5, Volvo VDS-4.5
- Cold cranking to −30°C (−22°F)
- Meets the requirements of DFS 93K222
- Cold cranking to −30°C vs −20°C for 15W-40
- Good choice for Canadian winter routes
Use the AMSOIL heavy-duty lookup to cross-reference your engine make, model, year, and emissions tier.
Use the AMSOIL Heavy-Duty Lookup →AMSOIL DD15 Oil — Which Tier Is Right for You?
Not every truck or budget calls for the same product. AMSOIL makes multiple diesel oil tiers depending on the job.
| Product | Protection Level | Drain Interval | Best For |
|---|---|---|---|
| Signature Series Max-DutyDHD / DME / DEO | Top-tier synthetic diesel protection | OEM interval; beyond it with oil analysis | Owner-operators and fleets maximizing uptime |
| Heavy-Duty SyntheticADN / ADO / ADP | Full synthetic protection | OEM interval | Operators wanting synthetic protection at lower upfront cost |
| Commercial-GradeSBDT / SBDF | Synthetic-blend upgrade | OEM interval | Fleets upgrading from conventional oil |
All three tiers are CK-4 oils that meet the requirements of DFS 93K222. Run Detroit's interval for your duty cycle, and use oil analysis before going past it.
Why DD15 Fleets Should Run Oil Analysis
The DD15 runs EGR, which means soot loading is a real factor. Mileage alone does not tell you the full story.
A basic oil analysis sample checks the numbers that matter:
- → TBN: remaining acid-neutralizing reserve
- → Soot: soot loading and viscosity risk
- → Wear metals: iron, copper, chromium, aluminum
- → Coolant contamination: early warning for cooler or gasket problems
EGR cooler leaks are a known issue on higher-mileage Detroit engines. When coolant reaches the intake stream or oil, damage gets expensive fast.
Oil analysis can show glycol or sodium before symptoms are obvious.
| Analysis kit | A fraction of one oil change |
| Early EGR cooler detection | Major repair avoided |
| Confirmed drain extension | Fewer oil changes |
| Liner wear detection | Rebuild risk reduced |
Detroit DD15 Engine Oil — Common Questions
From owner-operators, fleet managers, and shop techs running the DD15 across North America.