By the numbers
What Diesel Repairs Really Cost: 434 Bills Owners Reported to NHTSA
Published · 5 min read
Ask a shop what a diesel repair costs and the honest answer is "it depends". Ask the owners who already paid and you get numbers. In their complaints to NHTSA, 434 owners of Power Stroke, Cummins and Duramax trucks wrote down the bill or the quote they were given.
Half of those bills are under $2,209. One in eight is over $10,000, and 36 of those 53 five-figure bills come from just two engines, the two with the same fuel pump.
What owners paid, by system
- Cooling / head gasket / oil coolermedian $4,000 (21 owners)
- Fuel systemmedian $3,700 (189 owners)
- EGRmedian $3,000 (18 owners)
- Turbo / boostmedian $3,000 (19 owners)
- Engine internalsmedian $1,250 (15 owners)
- DEF / SCRmedian $1,200 (20 owners)
- Stall or power loss, no part namedmedian $1,088 (22 owners)
- Sensors and electronicsmedian $410 (24 owners)
434 NHTSA owner complaints that state a repair bill or quote, out of 4,433 on ten diesel engine families (Power Stroke 7.3 to 6.7, Cummins 5.9 and 6.7, Duramax LB7 to L5P), pulled 2026-09-07 to 2026-10-16, filed 1999 to 2026. Dollars of the year filed, not adjusted for inflation; the bar runs from the lower to the upper quartile, the dark line is the median. What owners told NHTSA, not a price list.
The fuel system has the widest spread. Its middle half runs from about $1,800 to $9,400, because it holds both a $400 sensor and a $15,000 fuel-system replacement. The next three, cooling, the turbo and the EGR system, sit around $3,000 to $4,000 and their ranges are narrower.
Sensors and DEF are the cheap end. A typical sensor bill is about $400, and DEF repairs around $1,200.
What owners paid, by engine
- Duramax LML (2011-2016)median $10,168 (28 owners)
- 6.7 Power Stroke (2011-2026)median $8,100 (62 owners)
- 6.7 Cummins (2007.5-2018)median $2,600 (37 owners)
- 6.0 Power Stroke (2003-2007)median $2,577 (99 owners)
- 5.9 Cummins (1994-2007)median $1,700 (67 owners)
- Duramax LB7-LMM (2001-2010)median $1,300 (32 owners)
- 7.3 Power Stroke (1994.5-2003)median $1,063 (79 owners)
434 NHTSA owner complaints that state a repair bill or quote, out of 4,433 on ten diesel engine families (Power Stroke 7.3 to 6.7, Cummins 5.9 and 6.7, Duramax LB7 to L5P), pulled 2026-09-07 to 2026-10-16, filed 1999 to 2026. Dollars of the year filed, not adjusted for inflation; the bar runs from the lower to the upper quartile, the dark line is the median. What owners told NHTSA, not a price list.
Two engines stand apart: the Ford 6.7 Power Stroke and the Duramax LML, both with medians above $8,000. They are the two engines in this set with the Bosch CP4.2 high-pressure pump. When a CP4 fails, it can shed metal into the fuel, and the fix becomes pumps, injectors, lines, rails and sometimes the tank. Fuel-system bills on those two engines have a median of $11,000. On the other engines, $2,589.
"They had to replace the entire fuel system plus replaced all injectors which now has an open invoice of $15,923.97."
Owner of a 2021 F-450 6.7, after the truck shut down on the highway, 2025. NHTSA complaint 11676722
The older engines look cheap partly because their bills are older. A 7.3 Power Stroke bill filed in 2004 is in 2004 dollars, and the 6.0's median of about $2,600 covers bills going back to the mid-2000s.
"I have to have this vehicle working so I got it repaired at a cost of $16,145."
Owner of a 2016 GMC Sierra 3500 Duramax, after a CP4 failure on the freeway, 2023. NHTSA complaint 11532754
How to use these numbers
- Budget for the expensive failure your engine is known for. On a CP4 truck that is the fuel system; on a 6.0 it is the coolers and head gaskets; on a 5.9 24-valve the VP44 pump. Our buyer's checklists list each engine's budget items.
- Ask about coverage before you pay. Several of the largest bills are for failures that recalls or extended coverage now address on some trucks. Run the VIN with our VIN lookup first.
- Get a written quote and a second opinion on any five-figure job, and ask whether the quote is for a full fuel-system replacement or the pump alone.
How we counted
We took every dollar amount between $150 and $30,000 in a sentence that talks about a repair, a quote or a bill, and left out sentences about buying the truck, financing, towing, rentals and deductibles. We also left out general claims such as "owners pay up to $20,000": a form letter on 2019-2020 Ram trucks repeats one of those in about a dozen complaints. The largest remaining amount in a complaint is its bill. We read samples, including every bill over $14,000, to check the rules.
What we cannot tell you
- A price list. These are what owners chose to report, in the dollars of the year they wrote, and often the worst cases.
- Labor rates where you live. Bills mix dealer and independent shops across 27 years.
- The newest trucks. The L5P and 2019 and newer Ram have too few stated bills to chart.
FAQ
How much does a CP4 fuel pump failure cost to fix?
In owner complaints on the Ford 6.7 Power Stroke and the Duramax LML, the median fuel-system bill is about $11,000, and several owners report $15,000 to $24,000 when the engine or the whole fuel system was replaced. Check recalls and coverage by VIN before paying.
What is the most expensive repair on a diesel truck?
In these complaints, the five-figure bills are mostly fuel-system replacements after a CP4 failure and engine replacements. By system, the fuel system has the highest upper range; cooling, turbo and EGR jobs typically run $3,000 to $4,000.
How much does a diesel DEF repair cost?
The median DEF bill owners reported is about $1,200, with the middle half between $800 and $2,000. DEF heaters, pumps and sensors are the usual parts.
Are older diesels cheaper to fix?
Their reported bills are lower, but many were filed 10 to 20 years ago in older dollars. The bigger difference is the fuel system: five-figure fuel-system bills are far rarer on the engines without a CP4 (9, against 33 on the Ford 6.7 and LML).
Go deeper
- CP4 pump: which diesel trucks have it · Five owners on the day their CP4 failed
- Duramax LML problems · 6.7 Power Stroke problems by year
- Repair plans with parts and rough labor · Recalls by engine
Sources. NHTSA owner complaints database (US government public domain), the complaint sets of our ten diesel engine articles, pulled 2026-09-07 to 2026-10-16 and filed 1999 to 2026. Amounts are what owners wrote, not verified invoices, and are not adjusted for inflation. Quotes normalized for capitalization; complaint numbers given so you can read them in full. Torque Index takes no paid placement and does not provide repair services.