The 6.7 Cummins is the most powerful engine option offered to Dodge RAM 2500 and 3500 owners. However, some worry that this power can come with a hefty price tag.
On average, you should expect to spend between $850-$1,100 per year maintaining your 6.7 Cummins engine.
This cost is higher than average, even compared to other full-size trucks. You may be able to save some money doing a bit of the maintenance yourself.
Below, we’ll discuss some common repairs your 6.7 Cummins engine may need, as well as the recommended maintenance schedule. Keep reading to learn more.
Recommended Maintenance Schedule for a 6.7 Cummins Engine
The 6.7 Cummins’s recommended maintenance schedule outlines all the services and inspections you may need throughout the engine’s first 150,000 miles.
Keeping up with this schedule is key to ensuring your engine functions well for as long as possible. See the table below for some of the recommended maintenance.
|7,500 miles||Change engine oil and engine oil filter (for 2007-2012 models)
Check diesel exhaust fluid and add if necessary
Inspect front end and lubricate if needed
Inspect CV or universal joints and lubricate if needed
|15,000 miles||Change engine oil and engine oil filter (2013+ models)
Replace fuel filters
Replace front and rear differential fluids
|22,500 miles||Replace cabin air filter
Inspect brake linings
Check and adjust the parking brake
Inspect drive belt, adjust if necessary
Inspect wheel bearings
|30,000 miles||Replace engine air filter
Replace automatic transmission fluid and filter (for Aisin AS69RC transmission)
Replace transfer case fluid
|60,000 miles||Replace automatic transmission fluid and filter (for 69RFE transmission)
Replace manual transmission fluid
|67,500 miles||Replace crankcase ventilation (CCV) filter (for 2007-2018 models)|
|75,000 miles||Replace CCV filter (for 2019+ models)|
|97,500 mile||Flush engine cooling system (for 2007-2012 models)
Replace power steering flui
|100,000 miles||Replace serpentine drive belt|
|150,000 miles||Flush engine cooling system (for 2013+ models)
Check and adjust valve lash (not required for models newer than 2018)
Each of the services listed above will have to be repeated each time your vehicle reaches the milestone again.
For example, all the services required at 7,500 miles will need to be repeated at 15,000 miles. This is in addition to those recommended at 15,000 miles.
Are 6.7 Cummins Engines Reliable?
In general, 6.7 Cummins engines are considered to be fairly reliable. To ensure your engine’s reliability, always make sure to be diligent about maintenance.
If you’re doing maintenance yourself, be sure to only use parts and fluids that meet or exceed the OEM specifications.
Dodge has been using these engines in their trucks since 2007. They don’t need repairs often, but earlier models are more prone to issues than newer models.
Common Issues with 6.7 Cummins Engines
Knowing what problems you may have to look out for before you purchase a vehicle with a 6.7 Cummins engine can be helpful. Below, we will discuss a few of the common issues and their associated repair prices.
Clogged Diesel Particulate Filter
A clogged diesel particulate filter (DPF) is most common on older engines and those with higher mileage.
Cummins originally tried to avoid using diesel exhaust fluid in these engines, leading the diesel to run richer to reduce emissions. However, this led to more soot, which can clog the DPF.
Engines manufactured from 2013 to now use diesel exhaust fluid. This helps reduce the potential for clogging in newer engines. However, it can still be a problem as your truck racks up mileage.
A clogged DPF results in pressure build-up, leading to more heat and stress on the engine. If the DPF is clogged, gases cannot escape.
If this is a problem in your engine, you may experience power loss or a longer crank. Your check engine light might also come on, or the vehicle may switch into reduced power mode.
Diesel particulate filters are not cheap to replace. Typically, the part alone will cost over $1,000. If you need a short-term solution, you can try cleaning out the build-up inside the filter.
Head Gasket Problems
While head gasket issues are not incredibly common, they are more prevalent in these engines than others. The cause is not clear, but it may be due to the engine’s high cylinder pressure.
A blown head gasket will usually cause coolant to leak into the combustion chambers. This often results in a white, sweet-smelling smoke. Other symptoms include a coolant leak or overheating.
Thankfully, a head gasket does not have to be an expensive repair. The part will usually cost only $100-$200. Labor costs can add a significant amount to the total cost, so you may want to replace it yourself if you have the necessary skills.
Excessive Fuel Dilution
The 6.7 Cummins engine manages regeneration by trapping small fuel particles in the DPF for cleaner emissions. Because of this, up to 5% fuel dilution is normal. However, excessive fuel dilution can interfere with the oil’s ability to lubricate and protect the engine.
Because the engine does not use the 7th injector to introduce fuel into the exhaust system, the injectors can spray fuel into the exhaust stream during the exhaust strokes.
This allows small amounts of fuel to stick to the cylinder’s wall, where it may mix with the oil.
Fuel dilution occurs in almost every diesel engine. However, the 6.7 Cummins engine seems to have a lot. While it won’t cause immediate damage, it can cause certain parts to wear down quicker than usual.
Perform an occasional oil analysis to ensure there is not excessive dilution. You can mediate this problem by allowing your engine to warm up before driving and avoiding idling for too long.
While this is a more common issue on earlier 6.7 Cummins engines, turbocharger problems may happen no matter the vehicle’s year.
In addition to complete failure, there are several common turbocharger problems you may experience
Sticky VGT parts
Leaking oil seals
Compressor or turbine wheel damage
Turbos go through a lot of wear over time. Because of this, worn bearings are one of the most common problems. If they wear down, it can lead to excessive shaft play and cause complete failure over time.
Leaking oil seals are the other most common turbocharger problem. Usually, this is caused by not allowing your vehicle to reach the correct temperature before driving.
Turbo seals are very hot, and cold oil contacting these seals is a recipe for disaster.
Letting your vehicle warm up before driving, and letting it idle for a couple of minutes before turning off, will both help prevent turbo problems. This is especially important if your engine has over 100,000 miles on it.
Symptoms of turbocharger issues include slow spooling, excessive exhaust smoke, whining sounds, and overall poor performance. It’s important to be extra careful with your turbocharger because replacement is not cheap.
A new OEM turbocharger may cost up to $2,000. If you opt for a refurbished turbocharger, the total cost will be $1,000-$1,500.
Can You Maintain a 6.7 Cummins Engine Yourself?
If you have the skills, knowledge, and tools to perform basic maintenance yourself, doing so can save a significant amount of money. While some repairs will still have to be carried out by professionals, you can do many of the small tasks yourself.
The table below will outline the average cost of many parts and fluids you’ll need to maintain your engine. Make sure to always use OEM or equivalent equipment to ensure your engine functions at its peak.
|Part Name||Average Cost|
|Engine Oil Filter||$8-$15|
|Engine Air Filter||$40|
|External Transmission Filter||$25|
|Internal Transmission Filter||$40|
|Transfer Case Fluid||$30|
|Front Differential Fluid||$35|
|Rear Differential Fluid||$35|
|Diesel Exhaust Fluid||$15-$20|
6.7 Cummins Engine Maintenance KitsDoing these minor maintenance tasks yourself can save a good amount of money. Not having to pay a mechanic’s labor costs can decrease the overall cost of ownership for your vehicle.
Purchasing a maintenance kit for your engine can help keep your costs and time down. Cummins offers owners both premium and standard maintenance kits online for vehicles made between 1989-2019.
Each kit includes a lube filter, fuel/water separator, and three-gallon jugs of synthetic oil. The only difference between the standard and premium kits is the specific products you receive.
|Model Years||Online Prices||Parts Included|
|1994-1996 ||Premium: $118|
|1997-1999 ||Premium: $121|
|2003-2007 ||Premium: $112|
|2007-2009 ||Premium: $145|
|2010-2012 ||Premium: $175|
|Standard parts plus frame rail fuel/water separato|
|2019||Premium: $172||Standard parts|
The Bottom Line
A 6.7 Cummins engine is often considered one of the most reliable diesel engines. To keep it running well year after year, expect to spend anywhere from $800-$1,100 annually.
Doing some of the basic maintenance yourself will help keep this cost down. You should always follow the suggested maintenance schedule to keep your vehicle in peak operating condition.
As long as you do this, you should have no problem keeping your engine in good condition for up to 350,000 miles.