Which 6.7 Cummins Years To Avoid and Why? (Explained)

The Cummins engines are widely renowned for their durability and reliability, and the 6.7 or B6.7L Cummins is one of its most well-received engines. The 6.7 Cummins is a diesel engine from the latest Cummins B series featuring a straight six-cylinder and 24 valve turbodiesels to offer unmatchable power and reliability.

However, every engine has its fair share of limitations, and the 6.7 Cummins is no exception either. As a result, common troubles like clogged diesel particulate filter, turbocharger failure, head gasket, or EGR cooler malfunctioning might occur.

Continue reading the following article to discover why exactly the 6.7 Cummins engines are better to be ignored and which 6.7 Cummins years model you should avoid considering.

About 6.7L Cummins

Cummins Engine Company was initially founded in 1919 but got reconstructed as Cummins in 2001 and Cummins has been one of the most trusted companies to offer some legendary engines.

The Cummins B series is one of the most powerful and reliable engine lineups. Also, widely used in auto appliances such as trucks, buses, and construction equipment.

One of the most known and used engine models of the B series is the 6.7L. The first 6.7 Cummins engine model was officially introduced in the middle of 2007 with the RAM 2500 and 3500 pickup trucks.

The 6.7 Cummins is available in standard output (ST) and high output (HO). Also, available in various size options and can offer 150 up to 420 Horsepower, as well as 660-850 lb-ft torque.

Later on, the 6.7 engine has been used in various other medium-duty trucks, motorhomes, and school buses.

Which Vehicle Models Particularly Feature 6.7 Cummins?

The following vehicle models are equipped with the 6.7 Cummins engine:

  • RAM 2500 Heavy-Duty Pickup Truck Models
  • RAM 3500 Heavy-Duty Pickup truck Models
  • 3500 Chassis Cab Models
  • 4500 Chassis Cab Models
  • 5500 Chassis Cab Models

Worst 6.7 Cummins Years To Avoid: (List of Years)

Cummins B series for delivering a solid, powerful, and reliable diesel engine.

Some of the Cummins B engine models are considered the world’s most popular and trustable diesel engines.

Technically, no engine can be faultless and perfect, the 6.7 Cummins also falls under that category.

Even the 6.7 engine was pretty famous in its initial era, where most users seemed to really enjoy their journey with that engine.

But issues eventually become unavoidable, and users often complain about steering, engine, electrical, suspension, or exhaust issues due to the 6.7 engine’s potential designing, manufacturing as well as technical Lacking.

Thus, avoid the following years’ 6.7 engines unless you are willing to experience the major issues that occur in those models:

Years To Avoid

Major Reasons

2007 Dodge 6.7 Cummins

1. Due to general steering troubles, extreme front end shaking, tie rod and drag link prematurely fail.

2. Engine troubles like visible oil leaks, the check warning engine light stays on without prior reasons or engine failure.

3. Electrical problems like faulty or bad TIPM, difficulty in engine start-up.

2008 Dodge 6.7 Cummins

1. Due to death wobble, unusual cranking sounds, and leakage on the steering box.

2. Additionally, exhaust, suspension, and engine failure were found and reported

2011 Dodge 6.7 Cummins

1. Due to major suspension issues like fracture tie rod and dead wobble

2. Engine troubles such as camshaft failure, difficulty starting, and poor speed or visible loss of engine power

5 Major Problems of 6.7 Cummins:

In this section, I will address and elaborately discuss the five most common problems of the 6.7 Cummins engine, which made them unreliable and worth avoiding.

Before moving toward the main discussion, let’s have a glance at the major issues and cost estimation for solving them-

Problem:Estimated Repair CostEstimated Labor Expense
1. DPF Clogging Issues$2k – $3k  (Labor Cost Included)
2. Turbocharger Failure$5,303 – $7,597$581 – $733
3. Head Gasket Problems$2,680 – $2,854$661 – $834
4. Fuel Dilution Issues$350 or more (Parts & Labor Cost Included)
5. EGR Cooler Problems$2,700 (Including Labor)

1. DPF Clogging Issues

The 6.7 Cummins engine has a very common and significant issue that most users and auto experts have reported. According to their real-life experience, the Diesel particulate filter or the DPF tends to clog pretty quickly and frequently.

Users mentioned common symptoms such as engine power loss, long crank, lowered power mode, turbo running poorly, and suddenly engine fault codes popping up.

Reportedly the manufacturer avoided using diesel exhaust fluid (DEF) in the 6.7 engines, Due to the absence of DEF, the engine is supposed to run a bit on the richer side to reduce NOx emissions. This process allows more particulates or soot, which eventually clogs the DPF.

These DPF clogging issues were severely problematic in the earlier models, and to reduce further damage Dodge rolled out multiple PCM re-flashes.

In 2013, the manufacturer developed 6.7 engine models equipped with SCR emissions control systems and diesel exhaust fluid, which effectively helps to reduce the particulates and minimizes the chances of DPF clogging.

Is This Problem Expensive To Fix?

Reportedly, you can fix the DPF issue from any professional servicing center or workshop at $2k-$3k  and the labor expense is included within the estimated costing amount.

The aftermarket diesel particulate filters are available at approx. $1,000 or little over $1,000.

2. Turbocharger Failure

Another most commonly mentioned 6.7 Cummins engine trouble is the Turbo malfunction or turbocharger complete failure and which mostly occurs in 6.7 engine’s earlier model users.

Since turbochargers naturally consume a lot amount of abuse, the malfunctioning or failure can be unavoidable overtimes.

Other common symptoms were slow spool, poor performance, excess smoke from the exhaust, oil loss, and whining sounds.

Besides noticing complete turbocharger failure, some other commonly reported Turbo related issues were premature seals problem or oil leaking from the seals, excess shaft play due to premature bearings wear, clinging VGT parts, and the compressor or turbine wheel deterioration.

Consumers also mentioned that the most common turbo problems occur at around 120,000 miles.

Is This Problem Expensive To Fix?

It is one of the most expensive repair servicing of 6.7 Cummins engines. Reportedly, servicing from any professional servicing center will cost between $5,303 and $7,597, and the labor expense will stay between $581 and $733.

New OEM turbochargers for 6.7 Cummins are available in the north at $1,000-$1,500.

3. Head Gasket Problems

According to numerous user reports as well as expert reviews, the 6.7 Cummins engine runs into the head gasket problems quite frequently, and consumers have to deal with the servicing very often.

This head gasket failure has been occurring most probably due to either the sheer power and torque that the manufacturer makes for the 6.7 or high cylinder pressures might be causing the trouble.

Users also reported encountering common symptoms such as white smoke coming out from the exhaust, an unusual sweet smell coming due to coolant burning, a blown head gasket that allowed oil to mix coolant system, and prompt overheating due to high pressure in coolant or coolant pour out of the tank.

However, the good news is head gasket failure issue of the 6.7 engine is less common and causes less severe damage compared to the previously launched 5.9 engines.

Is This Problem Expensive To Fix?

It is another expensive repair and if you are taking your vehicle to any professional workshop, it will cost you between $2,680 and $2,854, and the labor expense will stay between $661 and $834.

4. Fuel Dilution Issues

Reports claim that encountering fuel dilution issues in the 6.7 diesel engine’s oil is kind of natural due to the way the manufacturer designed and built the engine to manage regeneration.

In the regeneration managing process, the engine is supposed to trap the external particulates in the DPF and burn for cleaner emissions.

Unfortunately, the 6.7 engine does not use the 7th injector to raise fuel into the exhaust, and while the cylinder exhaust strokes, the 6.7 engine’s fuel injectors spray a good amount of fuel into the exhaust stream.

As a result, this entire process allows fuel to adhere to the cylinder wall and mix with the oil to cause dilution.

Is This Problem Expensive To Fix?

Cummins has launched a new oil analysis program and under this program, you can get the oil analysis done at approx. $350 or more (Including oil, oil filter, labor, and disposal costs)

5. EGR Cooler Problems

EGR cooler failure is not a new issue that only occurs with 6.7 Cummins engine-contained vehicles, and it is a pretty common problem for most modern diesel trucks or other similar vehicles.

However, most long-term diesel engine owners are already well aware of this trouble, and the EGR issues mostly occur because 6.7 engines are designed and built in a way that the EGR valve and cooler are supposed to run into several issues, especially with the higher mileage vehicles.

Fortunately, like all other 6.7 engine major issues, this one also has an easy solution. When the problem visibly pops up just delete the EGR system, and another solution is to clean up the EGR valve or simply replace it.

Is This Problem Expensive To Fix?

Taking your vehicle to any professional workshop, it will cost you approx. $2,700 (Including labor expense).

It is a relatively cheap repair service since professional assistance is not always required if you are maintaining its schedule maintenance.

How Long Will A 6.7 Cummins Last?

A 6.7 Cummins engine has a life expectancy between 250,000 and 350,000 miles.

How long do Cummins 6.7 Cummins injectors last?

With regularly scheduled maintenance and proper care, A 6.7 Cummins engine’s injector can last up to 250,000 or a few more miles.


Cummins brand is internationally famous for offering high-quality diesel engines and available in different sizes to meet the standard for delivering products that fulfill most equipment application demands.

But besides those engines’ excellent quality, engines like 6.7 also feature significant issues and costly repairing tasks. Therefore, do not rush over and take your time to make the best decision.

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