The Lemon Index
The 6.7 L inline-6 turbo diesel in the Ram 2500/3500 (Heavy Duty), model years 2007–2026. Owners filed 7,667 complaints about trucks with it (matched by VIN); 11% name the engine, #6 of the 12 diesel truck engine generations we track (1 = the most).
Known issues, checked against owner complaints
Problems owners of trucks with this engine name much more often than owners of other diesel truck generations (at least 1.5× the median, and 10+ complaints):
- The DPF / EGR / DEF system. 164 of 7,667 owner complaints (2.1%) mention the DPF, DEF or regen system, against a median of 0.1% for the other diesel truck generations we track.
DPF regeneration frequency. Truck began exhaust regeneration at frequent intervals. Truck produced check engine light for "regen frequency P2459". Problem verified by dealer. Cause of the issue is unknown.
2022 owner · NHTSA complaint 11689162 - The turbo. 129 of 7,667 owner complaints (1.7%) mention the turbo, against a median of 1.0% for the other diesel truck generations we track.
Heater grid fell of got into motor had to replace the motor and fuel lines, injectors, and turbo. Cost me over 30K cash. My wife withdrew from her retirement so we could afford to replace the motor. Then I had to take a job and move to be able to pay the truck off.
2016 owner · NHTSA complaint 11775735
Also often talked about, but not standing out in complaints to NHTSA: the EGR system (51 of 7,667, 0.7%, peers 0.3%). That doesn't mean it never happens, only that owners rarely file it with the government.
What YouTube owners say Tone 0-100, higher = more praise than trouble.
Average owner tone 40/100 across 19 model years, from 160 videos about this engine and its cars.
Most-watched videos
- 6.7 cummins EGR/DPF delete kit part 1 1,273,374 views
- What Caused This 6.7L Cummins to COMPLETELY Lock Up? 1,065,199 views
- BEFORE vs AFTER 6.7 Cummins Delete 5th Gen 1,022,192 views
Counted from video titles and captions: praise words against trouble words, weighted by views. Videos only count when the title names this engine or a car that had only this engine in those years.
Owner complaints by model year
Counts of complaints filed so far. Older trucks have had longer to collect them, and popular years draw more because more were sold: no one reports sales by engine, so there's no per-truck rate. Compare the shares below instead.
What owners complain about
Share of this engine's complaints that name each area (one complaint can name several).
What owners write
| Complaints that | Count | Share | Median, other diesel truck engines |
|---|---|---|---|
| Say the engine stalled, shut off or lost power | 494 | 6.4% | 7.8% |
| Mention the DPF, DEF or regen system | 164 | 2.1% | 0.1% |
| Mention a "death wobble" | 158 | 2.1% | 0.2% |
| Mention the turbo | 129 | 1.7% | 1.0% |
| Mention the CP4 or the high-pressure fuel pump | 87 | 1.1% | 0.3% |
| Mention coolant loss or overheating | 65 | 0.8% | 0.8% |
| Mention the EGR system | 51 | 0.7% | 0.3% |
| Mention an injector | 33 | 0.4% | 2.5% |
| Mention a fuel leak | 21 | 0.3% | 0.5% |
| Mention an oil leak | 15 | 0.2% | 0.5% |
Counted from the owner's own words in each complaint (all of the truck, not only the engine). A share, not a failure rate.
When problems show up
Half of the owners who gave a mileage reported the problem between 17,000 and 84,000 miles; the middle report was at 44,000 miles (2,929 complaints with a mileage).
Recalls that name this engine 9
23V060000 Feb 2023 Electrical System
Chrysler (FCA US, LLC) is recalling certain 2021-2023 Ram 2500, 3500, 3500 Cab Chassis, and 4500, 5500 Cab Chassis vehicles equipped with a Cummins 6.7L Turbo Diesel engine. An electrical short may occur in the heater grid relay with the ignition on or off.
Fix. Owners are advised to park outside and away from structures until the recall repair is complete. Dealers will replace the relay, free of charge. This will be a Phased campaign. Phase 1 will include 2023 model year vehicles. FCA US will notify dealers on or about 3/23/2023 and begin notifying owners on or about 4/5/2023. Phase 2 will include 2022 model year vehicles and Phase 3 will include 20
22V642000 Aug 2022 Engine And Engine Cooling
Chrysler (FCA US, LLC) is recalling certain 2022 Ram 3500, 3500 Cab Chassis, Ram 2500, and 4500 and 5500 Cab Chassis vehicles equipped with Cummins 6.7L turbo diesel engines. The engine control module (ECM) may have been built with a misaligned capacitor that can short-circuit, resulting in an internal loss of communication.
Fix. Dealers will replace the ECM, free of charge. Owner notification letters were mailed October 20, 2022. Owners may contact FCA US, LLC customer service at 1-800-853-1403. FCA US, LLC's number for this recall is Z87.
21V880000 Nov 2021 Fuel System, Diesel
Chrysler (FCA US, LLC) is recalling certain 2019-2020 Ram 2500, 3500 pickup trucks, and Ram 3500, 4500, and 5500 cab chassis vehicles equipped with Cummins 6.7L Turbo Diesel engines. The High Pressure Fuel Pump (HPFP) may fail, resulting in a sudden engine stall without warning.
Fix. Dealers will replace the HPFP, update the Powertrain Control Module (PCM) software, and inspect and replace additional fuel system components as necessary, free of charge. Interim owner notification letters to inform owners of the safety recall were mailed on January 4, 2022. Owner notification letters were mailed on May 17, 2022. Phase 2 owner notification letters are expected to be mailed on
21V798000 Oct 2021 Electrical System
Chrysler (FCA US, LLC) is recalling certain 2021-2022 Ram 3500, 2500 pickup trucks, and Ram 3500, 4500, and 5500 cab chassis vehicles equipped with Cummins 6.7L Turbo Diesel engines. An electrical short in the relay may cause a vehicle fire with the ignition on or off.
Fix. Owners are advised to park these vehicles outside of buildings or structures, and not near other vehicles, until the vehicle has been remedied. Dealers will inspect and, if needed, replace the Solid State Intake Heater Grid Relay ("Relay"); if FCA US Recall ID Y08 (NHTSA Recall ID 21V-163) is open, then insulating material will be applied to the Relay after inspection. Owner notification letters
21V439000 Jun 2021 Engine And Engine Cooling
Chrysler (FCA US, LLC) is recalling certain 2019-2020 Ram 3500, 4500, and 5500 cab chassis vehicles equipped with a Cummins 6.7L High Output engine. The engine calibration software may not warn about low oil volume.
Fix. Dealers will update the engine calibration software, free of charge. Owner notification letters were mailed June 25, 2021. Owners may contact FCA US LLC customer service at 1-800-853-1403. FCA US LLC's number for this recall is Y21.
21V163000 Mar 2021 Electrical System
Chrysler (FCA US, LLC) is recalling certain 2021 Ram 2500, 3500, and 3500, 4500, and 5500 Cab Chassis vehicles equipped with a Cummins 6.7L Turbo Diesel engine. An electrical short may occur in the Solid State Intake Heater Grid Relay, which could result in a vehicle fire.
Fix. Dealers will inspect and, if needed, replace the Solid State Intake Heater Grid Relay ("Relay"); if FCA US Recall ID Y08 (NHTSA Recall ID 21V-163) is open, then insulating material will be applied to the Relay after inspection. Customers are advised to not park these vehicles inside of buildings or structures, or near other vehicles until the vehicle has the final repair completed. Owner notifica
Show all 9
17V562000 Sep 2017 Engine And Engine Cooling
Chrysler (FCA US LLC) is recalling certain 2013-2017 RAM 2500, 3500, 3500 Cab Chassis, 4500 Cab Chassis, and 5500 Cab Chassis vehicles, equipped with Cummins 6.7L Turbo Diesel engines that have Concentric-brand water pumps without a vent hole. These water pumps may leak coolant.
Fix. Chrysler will notify owners, and dealers will replace the water pumps, free of charge. The recall began February 26, 2018. Owners may contact Chrysler customer service at 1-800-853-1403. Chrysler's number for this recall is T51.
15V592000 Sep 2015 Engine And Engine Cooling
Chrysler (FCA US LLC) is recalling certain model year 2016 Ram 2500, 3500, 3500 Cab Chassis and 4500/5500 Cab Chassis trucks manufactured July 31, 2015, to August 13, 2015 and equipped with a 6.7L Cummins Diesel engine. In the affected vehicles, the Engine Control Module (ECM) may short circuit, causing the engine to stall without warning.
Fix. Chrysler will notify owners, and dealers will replace the ECM, free of charge. The recall began on December 21, 2015. Owners may contact Chrysler customer service at 1-800-853-1403. Chrysler's number for this recall is R52.
08V641000 Dec 2008 Engine And Engine Cooling
Chrysler is recalling 108,429 my 2007-2008 dodge ram 2500 and 3500 pickup trucks equipped with 6.7l diesel engines. A silencer pad can sag and contact the exhaust gas recirculation (egr) cooler.
Fix. Dealers will add a bracket to support the engine compartment silencer pad adjacent to the egr cooler. The recall is expected to begin during december 2008. Owners may contact chrysler at 1-800-853-1403.
NHTSA recalls on these trucks and years whose text names this engine (its size, or diesel / Cummins / Duramax / Power Stroke). The rest (brakes, air bags, wiring ...) are on each truck year's page.
Trucks with this engine
In owners' words
Heater grid fell of got into motor had to replace the motor and fuel lines, injectors, and turbo. Cost me over 30K cash. My wife withdrew from her retirement so we could afford to replace the motor. Then I had to take a job and move to be able to pay the truck off.
2016 Ram 2500/3500 (Heavy Duty) owner · NHTSA complaint 11775735
On my 2019 RAM 3500, I reported a problem with th eNHSTA back in 2023, and NO response yet. This is about the integrated brake controller, that provides NO electrical signal to stop the towed trailer at speeds what apear to be below 35MPH. This is a very dangerous failure on these trucks.
2019 Ram 2500/3500 (Heavy Duty) owner · NHTSA complaint 11767624
Trucks ignition system does not work properly; manufacturer has no way to diagnose the problem. possible fire hazard? drive system, was not built to factory standards, dealer advised to not to drive out of fear of blowing up while driving down the road.
2026 Ram 2500/3500 (Heavy Duty) owner · NHTSA complaint 11766831
Against the other diesel truck engine generations
| Engine | Years | Complaints | Name the engine | Name the fuel system | Stalled or lost power | Recalls naming it |
|---|---|---|---|---|---|---|
| 6.0 Power Stroke | 2003–07 | 1,708 | 34% | 16% | 31% | 2 |
| 6.4 Power Stroke | 2008–10 | 572 | 28% | 7% | 11% | 2 |
| Duramax L5P | 2017–26 | 1,229 | 16% | 10% | 14% | 2 |
| 7.3 Power Stroke | 1999–03 | 2,049 | 15% | 5% | 12% | 1 |
| Duramax LML | 2011–16 | 779 | 13% | 20% | 17% | 0 |
| 6.7 Cummins | 2007–26 | 7,667 | 11% | 8% | 6.4% | 9 |
| 6.7 Power Stroke | 2011–26 | 5,640 | 10% | 11% | 7.8% | 6 |
| Duramax LBZ | 2006–07 | 186 | 8% | 5% | 7.0% | 0 |
| Duramax LMM | 2007–10 | 385 | 8% | 6% | 5.2% | 0 |
| Duramax LB7 | 2001–04 | 592 | 7% | 17% | 5.4% | 1 |
| Duramax LLY | 2004–06 | 374 | 7% | 11% | 7.8% | 0 |
| 5.9 Cummins | 1999–07 | 3,245 | 4% | 7% | 5.0% | 0 |
Shares of each engine's own complaints, matched by VIN. They show what owners complain about, not how often trucks break. Every diesel truck engine compared
Quick answers
Is the Cummins 6.7 (Ram) reliable?
No one reports sales by engine, so there's no per-truck score. Of the 7,667 complaints owners filed about trucks with it, 11% name the engine, #6 of 12 diesel truck engine generations we track (1 = the most). 164 (2.1%) mention the DPF, DEF or regen system, against 0.1% for its peers. 129 (1.7%) mention the turbo, against 1.0% for its peers.
What trucks have the Cummins 6.7 (Ram)?
In our data: the Ram 2500/3500 (Heavy Duty), model years 2007–2026, matched by the VIN in each owner complaint.
What are the most common 6.7 Cummins problems?
In owner complaints to the government: brakes, steering, electrical.
How many recalls name the 6.7 Cummins?
9 NHTSA recalls on these trucks name it.
Source: NHTSA owner complaints (FLAT_CMPL + COMPLAINTS_RECEIVED_2025-2026), received through 20261109; engines: NHTSA vPIC VIN decoder; NHTSA recalls API. Engine names and years: Cummins / Ram.