The 6.7 Cummins is a 6.7-liter (408 cubic inch) inline-six turbo diesel with 24 valves and high-pressure common-rail injection, used in Ram 2500 and 3500 pickups since the 2007.5 model year. It holds about 12 quarts of oil with a filter change in Ram pickups, and its firing order is 1-5-3-6-2-4. Ram’s power ratings rose over the years, from 350 hp at launch to more than 400 hp for later high-output versions.
6.7 Cummins specs
| Configuration | Inline six, 24 valves, turbocharged diesel |
|---|---|
| Displacement | 6.7 L (408 cu in) |
| Bore x stroke | 4.21 x 4.88 in (107 x 124 mm) |
| Fuel system | High-pressure common rail |
| Turbocharger | Variable geometry: Holset HE351VE (2007.5-2012), HE300VG (2013-2018) |
| Firing order | 1-5-3-6-2-4 |
| Oil capacity | About 12 quarts with filter (Ram 2500/3500) |
| In Ram pickups | 2007.5 to present |
6.7 Cummins oil capacity and oil changes
Plan on about 12 quarts with a new filter, and confirm the exact quantity and the oil specification for your year in the owner’s manual. Diesel oil changes are larger and, under severe use such as heavy towing, more frequent than on gas engines; follow the maintenance schedule for your truck and how you use it.
Cylinder numbering
Cylinders on an inline six are numbered in a single row, with cylinder 1 at the front of the engine nearest the radiator and cylinder 6 nearest the firewall. Combined with the 1-5-3-6-2-4 firing order, that tells you which injector or cylinder a diagnostic code or a misfire refers to; see engine misfire for how cylinder-specific codes work.
6.7 Cummins generations in Ram trucks
- 2007.5-2012: the first 6.7, with a diesel particulate filter and the HE351VE turbo.
- 2013-2018: updated engine with the HE300VG turbo; Ram heavy-duty pickups added selective catalytic reduction with diesel exhaust fluid (DEF).
- 2019 on: revised engine for the fifth-generation Ram heavy duty, with higher ratings, especially in high-output form.
Parts differ between these ranges, which is why the engines and turbos we carry are listed by model year. Replacement turbos are covered on our 6.7 Cummins turbo page, and common faults in 6.7 Cummins problems.
6.7 vs 5.9 Cummins
The 5.9 Cummins it replaced is also an inline six with the same 1-5-3-6-2-4 firing order. The 5.9 came in 12-valve, 24-valve and, from 2003, common-rail versions; see 12 valve vs 24 valve vs common rail. For how the Cummins compares with GM and Ford diesels, read Cummins vs Duramax vs Powerstroke.
6.7 Cummins engines we carry
We carry D&J Precision Machine 6.7 Cummins short blocks, long blocks and Ready Run complete engine packages for 2007.5 and later Ram 2500 and 3500 trucks, listed by model-year range. See them on our 6.7 Cummins engines page, or browse the 5.9 Cummins engines for 2003-2007 trucks.
More guides: 5.9 vs 6.7 Cummins · 5.9 Cummins specs.
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