Complete Oil Specifications
Your 2023 Ram 3500 6.7L Cummins Turbo Diesel requires SAE 15W-40 heavy-duty diesel engine oil meeting API CK-4 standards. In temperatures consistently below 0°F (-18°C), 5W-40 full synthetic CK-4 oil may be substituted for improved cold-start protection.
Quick Reference
| Specification | Value |
|---|---|
| Viscosity | 15W-40 |
| API Rating | CK-4 |
| Capacity (with filter) | 12.0 quarts |
| Oil Filter | Mopar 68001583AA |
| Normal Interval | 15000 miles |
Why CK-4 and 15W-40 Are Critical for the Cummins
The 6.7L Cummins B6.7 is a medium-duty-derived inline-six diesel producing up to 420 horsepower and 1,075 lb-ft of torque. It operates at combustion pressures far exceeding those of gasoline engines, and its high-pressure common-rail (HPCR) injection system — with injection pressures up to 36,000 psi — demands oil with superior soot-handling capacity, anti-wear chemistry, and oxidation resistance. The API CK-4 rating supersedes the previous CJ-4 spec and specifically addresses increased oxidative stability requirements for modern diesel engines with EGR (exhaust gas recirculation).
Using incorrect oil will:
- ❌ Allow soot agglomeration and premature oil thickening from EGR-related combustion byproducts
- ❌ Risk injector and high-pressure fuel pump damage if gasoline engine oil (API SP) is used
- ❌ Cause excessive wear at the camshaft and roller followers at high torque output levels
Cummins-Approved Oil Brands
-
✅ Shell Rotella T4 Triple Protection 15W-40
-
✅ Shell Rotella T6 Full Synthetic 5W-40
-
✅ Mobil Delvac 1300 Super 15W-40
-
✅ Valvoline Premium Blue 15W-40
-
✅ Mopar Genuine Diesel Engine Oil 15W-40
Cold Climate Note: Below 0°F (-18°C), switch to a 5W-40 full synthetic CK-4 oil such as Shell Rotella T6 5W-40. The 5W winter rating provides faster oil flow to the turbo bearings and fuel pump at extreme cold-start.
Oil Filter Options
- OEM: Mopar 68001583AA (spin-on)
- Fleetguard LF16035 — the Cummins factory OEM equivalent, often preferred by Cummins specialists and fleet operators
- Wix 57035, Baldwin B7600 — quality aftermarket alternatives
Fleetguard is Cummins’s own filtration brand and the filter specification against which the engine was designed. Either the Mopar or Fleetguard filter is appropriate for warranty purposes.
Severe Service Check
You need the 7500-mile interval if you:
- Tow at or near maximum gross combined weight rating (GCWR) regularly
- Idle frequently (PTO operation, remote start in cold climates)
- Operate in dusty or off-road environments
- Use B20 or higher biodiesel blends (which accelerate oil degradation)
- Make frequent short trips without reaching full operating temperature
Installation Details
Drain Plug Torque: 37 ft-lbs
OEM Filter: Mopar 68001583AA
Aftermarket Filters:
-
Fleetguard LF16035
-
Wix 57035
-
Baldwin B7600
Pro Tip: The 6.7L Cummins holds 12 quarts — have at least three 1-gallon jugs on hand. After filling, run the engine for 30 seconds, shut off, wait 5 minutes, then check the dipstick. Cummins engines can take a few moments for oil to fully circulate into the filter and galleries before the level stabilizes.
FAQs
What oil does a 2023 Ram 3500 6.7L Cummins take? SAE 15W-40 meeting API CK-4. Shell Rotella T4, Mobil Delvac 1300, and Valvoline Premium Blue are all excellent choices. Do not use gasoline engine oil (API SP) — it lacks the soot-handling additives required for diesel service.
How many quarts does it need? 12.0 quarts with a new filter, 11.0 without. The large sump is normal for this heavy-duty diesel.
Can I use 5W-40 instead of 15W-40? Yes, in cold climates (below 0°F) or if you prefer full synthetic year-round. Cummins approves both 15W-40 and 5W-40 in CK-4 grade. The 5W-40 (e.g., Shell Rotella T6) provides identical high-temperature protection with better cold-start flow.
Can I use CJ-4 oil if that’s what I have? CK-4 is backward-compatible with CJ-4-rated engines, but CJ-4 oil in a CK-4 engine is a downgrade. Use CK-4 for the 2023 Cummins.
How often should I change the oil? Every 15000 miles or 1 year under normal conditions. The Ram’s oil life monitor accounts for Cummins duty cycles, but many diesel owners on heavy towing schedules prefer 7,500-mile intervals as a conservative choice.
Does the Cummins have a diesel particulate filter (DPF)? Yes. The Ram 3500 Cummins is equipped with an SCR/DPF aftertreatment system. Use only low-ash CK-4 oil — high-ash oils accelerate DPF plugging and require forced regeneration cycles.
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Last verified: 2026-04-22 | Source: 2023 Ram 3500 Owner’s Manual