For the used-truck buyer

5.9 vs 6.7 Cummins, compared

The 5.9 (12-valve, 24-valve and common rail), the 6.7 that brought the emissions hardware, and the 2019+ 6.7 in the new Ram HD body. What fails, what was recalled, what the repairs cost, with sources and no verdicts.

At a glance

The identity rows are facts from our platform records; the counts are what this site documents for each engine today.

	5.9 Cummins	6.7 Cummins 2007.5-2018	6.7 Cummins 2019+
Years	1994-2007 Ram 2500/3500 (early MY2007 trucks still had the 5.9)	2007.5-2018 Ram 2500/3500 and 3500-5500 chassis cabs	2019-present Ram 2500/3500 and 3500-5500 chassis cabs (new HD body)
Fuel injection	Three generations: 12-valve P7100 P-pump (1994-early 1998), 24-valve VP44 (mid-1998-2002), common rail with CP3 (2003-2007)	Bosch CP3 common rail, in-tank lift pump	CP4-style pump on 2019-2020 (recall 21V-880 / Y78 replaces it with a CP3-style pump), CP3-style afterwards; in-tank lift pump
Turbo	Holset HX35W / HE351CW (wastegate)	Holset VGT: HE351VE (2007.5-2012 pickups), HE300VG (2013+)	Holset HE300VG-family VGT, electronic actuator
Emissions hardware	No EGR, DPF or DEF	EGR and DPF from launch; SCR with DEF added for MY2013	EGR, DPF and SCR with DEF
What changes inside the range	The fuel-injection generation (12-valve, 24-valve, common rail)	Emissions hardware: DPF only (2007.5-2012) or SCR/DEF (2013-2018)	Output tier (standard or High Output); same hardware generation
Documented failure modes	10 (9 verified)	14 (13 verified)	9 (9 verified)
NHTSA safety recalls naming the engine	9	5	8
Bulletins, programs and coverages	0	13	4
Repair recipes	4	6	3
Buyer's checklist	5.9 Cummins checklist	6.7 Cummins 2007.5-2018 checklist	6.7 Cummins 2019+ checklist

Power and torque are left out here: Ram rated the Cummins differently by year, transmission and truck, and our records do not track the ratings. The 2019-2020 pump change matters most to a buyer: check recall 21V-880 by VIN. Recall counts follow the years each engine was sold: a longer run collects more campaigns.

What fails, engine by engine

Most widespread first. Each failure links to its full record (symptoms, cause, diagnosis, fixes, sources). Complaint counts are NHTSA owner complaints matched to that failure by keyword (unadjudicated) and only compare failures on the same engine, not engines with each other. How we tier facts.

5.9 Cummins

10 documented failure modes

12v overflow valve weak (hard start / low power) verified Common · 1994-1998 only
53-block casting crack (24v ISB) verified Common · 1999-2002 only
APPS (throttle position sensor) failure / dead pedal (24v) verified Common · 1998-2002 only
Common-rail injector wear / nozzle carbon (03-07) verified Common · 2003-2007 only Repair budget: about $2,600-$2,800 in parts, plus parts we have no price for (recipe)
Fuel lift (transfer) pump failures verified Common · 1998-2004 only Repair budget: about $120-$1,950 in parts (recipe)
Head gasket failure on tuned common-rail trucks (03-07) verified Common · 2003-2007 only
Killer Dowel Pin (KDP) on the 12v P-pump engines verified Common · 1994-1998 only Repair budget: about $220-$520 in parts (recipe)
VP44 injection pump death (24v ISB) verified Common · 1998-2002 only Repair budget: about $2,100 in parts (recipe)
Intake grid heater / relay failures (cold starts) verified Occasional · 1998-2007 only
Turbo wastegate actuator seize / boost control (HX35W, HE351CW) aggregated Occasional

6.7 Cummins 2007.5-2018

14 documented failure modes

DPF clogging / regeneration problems verified Very common · NHTSA: 55 of 1,355 complaints · TSB 18-002-14 REV. B, TSB 18-002-14 REV. A, TSB 18-002-14
Holset VGT turbo sticking / actuator failure verified Very common · NHTSA: 40 of 1,355 complaints · TSB 11-001-08 Repair budget: about $3,250-$6,000 in parts, plus parts we have no price for (recipe)
DEF / SCR system failures (2013-2018) verified Common · 2013-2018 only · NHTSA: 43 of 1,355 complaints
Lift pump / fuel delivery weakness verified Common · NHTSA: 32 of 1,355 complaints · TSB 08-036 Repair budget: about $80-$860 in parts (recipe)
Water pump failure verified Common · NHTSA: 30 of 1,355 complaints Repair budget: about $230-$400 in parts, plus parts we have no price for (recipe)
Exhaust manifold cracking verified Common · NHTSA: 17 of 1,355 complaints
Grid heater 'killer bolt' ingestion verified Common · NHTSA: 17 of 1,355 complaints · TSB 9003585, TSB 18-005-13 Repair budget: about $270-$820 in parts (recipe)
EGR valve sooting / failure verified Common · NHTSA: 16 of 1,355 complaints Repair budget: about $650-$2,100 in parts, plus parts we have no price for (recipe)
Injector 'chuffing' / seal blow-by verified Common · NHTSA: 12 of 1,355 complaints · TSB 05175565A$, TSB 18-002-14 REV. B, TSB 18-002-14 REV. A and 1 more
Fan clutch failure (overheat while towing) verified Common · NHTSA: 7 of 1,355 complaints Repair budget: about $230-$400 in parts, plus parts we have no price for (recipe)
EGR cooler failure verified Common · NHTSA: 6 of 1,355 complaints · TSB 18-045-15 REV A, TSB 18-045-15, TSB 18-018-13 REV. A and 1 more Repair budget: about $650-$2,100 in parts, plus parts we have no price for (recipe)
CCV breather filter clogging verified Common · NHTSA: 1 of 1,355 complaints · TSB 18-045-15, TSB 18-030-14 REV. B, TSB 18-030-14 REV. A and 1 more
Fuel dilution of engine oil (failed regens) aggregated Occasional
Head gasket failure (tuned / overheated trucks) verified Rare · NHTSA: 3 of 1,355 complaints

6.7 Cummins 2019+

9 documented failure modes

CP4 high-pressure fuel pump failure and fuel system contamination (2019-2020 6.7) verified Very common · NHTSA: 66 of 318 complaints · 21V-880, 18-099-22 / 18-054-21, 14-008-22
DPF/SCR aftertreatment problems (2019+ 6.7) verified Common · NHTSA: 27 of 318 complaints · Emissions Recall Y43, Warranty Extension X97 (09-014-22) Repair budget: about $90-$1,200 in parts (recipe)
Grid heater bolt and relay failures (2019+ 6.7) verified Common · NHTSA: 22 of 318 complaints · 23V-060, 21V-798, 21V-163
Common-rail injector wear (2019+ 6.7) verified Common
EGR cooler failure (2019+ 6.7) verified Common Repair budget: about $90-$1,200 in parts (recipe)
Head gasket failure on tuned 2019+ 6.7 verified Common
In-tank lift pump failures (2019+ 6.7) verified Common
VGT turbo electronic actuator failure (HE300VG family) verified Common Repair budget: about $1,450-$6,850 in parts (recipe)
DEF quality / freezing inducements (2019+ 6.7) verified Occasional Repair budget: about $290-$340 in parts, plus parts we have no price for (recipe)

Same symptom, each engine

How many documented failures show each sign on each engine, and the most widespread one. Open a cell for every cause on that engine, ranked, with how to tell them apart.

Symptom	5.9 Cummins	6.7 Cummins 2007.5-2018	6.7 Cummins 2019+
Hard start / no-start	4 causes 12v overflow valve weak (hard start / low power)	2 causes Lift pump / fuel delivery weakness	3 causes CP4 high-pressure fuel pump failure and fuel system contamination (2019-2020 6.7)
Stalls while driving	1 cause Killer Dowel Pin (KDP) on the 12v P-pump engines	None documented	1 cause CP4 high-pressure fuel pump failure and fuel system contamination (2019-2020 6.7)
Power loss / limp mode	4 causes 12v overflow valve weak (hard start / low power)	6 causes DPF clogging / regeneration problems	4 causes CP4 high-pressure fuel pump failure and fuel system contamination (2019-2020 6.7)
White smoke	2 causes Common-rail injector wear / nozzle carbon (03-07)	3 causes DPF clogging / regeneration problems	3 causes Grid heater bolt and relay failures (2019+ 6.7)
Black smoke	1 cause 12v overflow valve weak (hard start / low power)	1 cause Holset VGT turbo sticking / actuator failure	None documented
Coolant loss	2 causes 53-block casting crack (24v ISB)	3 causes Water pump failure	2 causes EGR cooler failure (2019+ 6.7)
Engine noise	3 causes Common-rail injector wear / nozzle carbon (03-07)	7 causes Holset VGT turbo sticking / actuator failure	3 causes Grid heater bolt and relay failures (2019+ 6.7)
Misfire / rough running	2 causes Common-rail injector wear / nozzle carbon (03-07)	5 causes Holset VGT turbo sticking / actuator failure	1 cause Common-rail injector wear (2019+ 6.7)
DEF / DPF warnings	None documented	4 causes DPF clogging / regeneration problems	2 causes DPF/SCR aftertreatment problems (2019+ 6.7)

Trouble codes our records tie to failures on more than one of these engines: P0087 (fuel rail pressure too low) on 6.7 Cummins 2007.5-2018 and 6.7 Cummins 2019+; P2609 (intake air heater circuit) on 6.7 Cummins 2007.5-2018 and 6.7 Cummins 2019+.

Safety recalls

NHTSA safety recalls whose text names the engine, newest first, with NHTSA's own risk statement. Bulletins and programs are on each engine's recall page.

Engine	Campaign	Years	Risk (NHTSA)
5.9 Cummins	07V-093	2007	IMPROPER TIRE INFLATION PRESSURE CAN CAUSE TIRE FAILURE AND RESULT IN A CRASH WITHOUT WARNING.
5.9 Cummins	05V-462	2003-2005	THIS ERROR IS AN UNINTENDED ACTION THAT MAY RESULT IN A LACK OF TRANSMISSION PARK PAWL ENGAGEMENT AND POSSIBLY DELAYED REARWARD MOVEMENT OF THE VEHICLE.
5.9 Cummins	03V-033	2003	THIS CAN RESULT IN UNINTENDED ACCELERATION AND A REDUCTION IN BRAKING EFFECTIVENESS, INCREASING THE RISK OF A CRASH.
5.9 Cummins	02V-161	1997-1998	THIS COULD POTENTIALLY RESULT IN A LOSS OF THROTTLE CONTROL, INCREASING THE RISK OF A CRASH.
5.9 Cummins	01V-037	1994-1995	A THROTTLE THAT DOES NOT RETURN TO IDLE COULD RESULT IN UNEXPECTED ACCELERATION, INCREASING THE RISK OF A CRASH.
5.9 Cummins	98V-209	1998	THIS CREATES A SIGNAL WHICH IS MISINTERPRETED BY THE ENGINE CONTROL SOFTWARE, CAUSING A HIGH IDLE SPEED CONDITION.
5.9 Cummins	98V-207	1998	THIS CONDITION CAN ALLOW FUEL TO LEAK. IN THE PRESENCE OF AN IGNITION SOURCE, FUEL LEAKAGE CAN RESULT IN A FIRE.
5.9 Cummins	97V-126	1997	IF THE EXHAUST PIPE GENERATES SUFFICIENT HEAT, THE PAD MATERIAL CAN SMOLDER AND IGNITE ADJACENT MATERIALS RESULTING IN A VEHICLE FIRE.
5.9 Cummins	97V-068	1995	REDUCED POWER BRAKE ASSIST CAN RESULT INCREASING THE RISK OF A VEHICLE CRASH.
6.7 Cummins 2007.5-2018	17V-562	2013-2017	The leaking water pump can increase the risk of an engine compartment fire.
6.7 Cummins 2007.5-2018	15V-592	2016	An engine that stalls without warning increases the risk of a crash.
6.7 Cummins 2007.5-2018	14V-635	2011-2014	If the connectors overheat, the fuel heater may leak fuel, increasing the risk of a fire.
6.7 Cummins 2007.5-2018	08V-641	2007-2008	THIS COULD RESULT IN AN ENGINE COMPARTMENT FIRE.
6.7 Cummins 2007.5-2018	07V-093	2007	IMPROPER TIRE INFLATION PRESSURE CAN CAUSE TIRE FAILURE AND RESULT IN A CRASH WITHOUT WARNING.
6.7 Cummins 2019+	23V-060	2021-2023	An electrical short in the relay can result in an engine compartment fire with the ignition on or off, increasing the risk of injury.
6.7 Cummins 2019+	22V-642	2022	An internal loss of communication can result in a loss of drive power, increasing the risk of a crash.
6.7 Cummins 2019+	21V-880	2019-2020	An engine stall increases the risk of a crash.
6.7 Cummins 2019+	21V-798	2021-2022	A vehicle fire increases the risk of injury.
6.7 Cummins 2019+	21V-439	2019-2020	Low oil can damage the engine, causing an oil leak or a punctured engine block, increasing the risk of a fire.
6.7 Cummins 2019+	21V-163	2021	A vehicle fire increases the risk of injury.
6.7 Cummins 2019+	20V-511	2019-2020	A damaged engine block may leak oil, which can contact hot engine or exhaust components, increasing the risk of a fire.
6.7 Cummins 2019+	19V-498	2019	A fuel leak in the presence of an ignition source increases the risk of a fire.

A recall's remedy is free. Whether one is still open on a given truck is a VIN question: check at nhtsa.gov/recalls before paying for the same work.

Repair costs, in money

Parts budgets from our repair recipes, for the failures a recipe prices: Dave's Auto Center's prices where Dave's lists the part, approximate OEM and maker catalog prices (rounded) for the rest. Labor not included; not a quote.

Engine	Failure	Budget band
5.9 Cummins	Common-rail injector wear / nozzle carbon (03-07)	about $2,600-$2,800 in parts, plus parts we have no price for (recipe)
5.9 Cummins	Fuel lift (transfer) pump failures	about $120-$1,950 in parts (recipe)
5.9 Cummins	Killer Dowel Pin (KDP) on the 12v P-pump engines	about $220-$520 in parts (recipe)
5.9 Cummins	VP44 injection pump death (24v ISB)	about $2,100 in parts (recipe)
6.7 Cummins 2007.5-2018	Holset VGT turbo sticking / actuator failure	about $3,250-$6,000 in parts, plus parts we have no price for (recipe)
6.7 Cummins 2007.5-2018	Lift pump / fuel delivery weakness	about $80-$860 in parts (recipe)
6.7 Cummins 2007.5-2018	Water pump failure	about $230-$400 in parts, plus parts we have no price for (recipe)
6.7 Cummins 2007.5-2018	Grid heater 'killer bolt' ingestion	about $270-$820 in parts (recipe)
6.7 Cummins 2007.5-2018	EGR valve sooting / failure	about $650-$2,100 in parts, plus parts we have no price for (recipe)
6.7 Cummins 2007.5-2018	Fan clutch failure (overheat while towing)	about $230-$400 in parts, plus parts we have no price for (recipe)
6.7 Cummins 2007.5-2018	EGR cooler failure	about $650-$2,100 in parts, plus parts we have no price for (recipe)
6.7 Cummins 2019+	DPF/SCR aftertreatment problems (2019+ 6.7)	about $90-$1,200 in parts (recipe)
6.7 Cummins 2019+	EGR cooler failure (2019+ 6.7)	about $90-$1,200 in parts (recipe)
6.7 Cummins 2019+	VGT turbo electronic actuator failure (HE300VG family)	about $1,450-$6,850 in parts (recipe)
6.7 Cummins 2019+	DEF quality / freezing inducements (2019+ 6.7)	about $290-$340 in parts, plus parts we have no price for (recipe)

Going to look at one of these trucks? Decode its VIN for the exact engine, its recalls and failure modes, then take the buyer's checklist with you.

Look up a VIN 5.9 Cummins checklist 6.7 Cummins 2007.5-2018 checklist 6.7 Cummins 2019+ checklist

Method: built from the same records as the engine pages on 2026-11-01. Failure modes are tiered and sourced per record and ranked by how widespread they are; complaint counts come from keyword classification of NHTSA owner complaints (unadjudicated); recalls are NHTSA's records for the models and years each engine was sold in; budgets are our repair recipes' bands at their check-date prices. No verdicts here, documented risk only. Full disclosure model.