How Many Miles Can You Put On a 6.7 Cummins

Keen to know what the average mileage is on a 6.7 Cummins? Perhaps, you’re in the market for a used Ram truck? Is a 6.7 Cummins with over 200 miles still deemed a safe used purchase?

Ram claims the Cummins 6.7 engine to be good for 350,000 miles. The mileage is guaranteed if the scheduled services has been carried out timeously and no performance modifications have been done to the engine.

These engines are one of the 3 most reliable engines ever built, and is usually compared to competitors such as the Duramax and Powerstroke engines built by Isuzu Motors and Ford respectively. If you want to determine the overall health of the engine before purchasing a used truck of this mileage, you’d do well to have a deep oil analysis done.

This will be able to provide specific clues regarding engine wear rate without any major engine operation needed. By analyzing a sample of used engine oil, you can determine the amount of contamination and overall engine health.

Let’s look into some of the high mileage components that needs to be checked once the mighty 6.7 Cummins reaches mileage into the hundreds of thousands.

How Many Miles Can You Put On a 6.7 Cummins

With any high mileage engine, albeit one with a good reputation, you want to determine of the routine maintenance has been carried out. Check the honesty plan for regular services and routine maintenance work. If you are not mechanically minded, have a knowledgeable friend accompany you, or a qualified mechanic to the check a few suspension components out.

Being a truck of this size, you want to make sure you inspect the following undercarriage components first:

  • Front suspension
  • Ball Joints
  • U-joints
  • Wheel bearings
  • Drive shafts

These suspension components seem be the typical wear points on these beasts and are usually first to go before the engine comes close to giving up the ghost. Inspect the drive shafts for excessive play and check all rubber seals for leaks and tears.

Like with any vehicle, the Ram isn’t exempt of the usual wear and tear items that needs replacement after a while, irrespective of how well it was looked after. As the truck ages there are some higher costing maintenance items that will start to rear their ugly heads.

Higher costing maintenance items can include but not limited to:

  • Brake Rotors
  • Wheel bearings
  • Tie-rod ends
  • Alternator
  • Starter motor
  • Injectors
  • Clutch kits

There were also reports of emission control issues on a few of these trucks since they don’t like stop/go, low speed driving too often. The main purpose for these trucks were not for light work and slow disrupted driving, but rather designed for long hauls with heavy loads and towing. So if you’re planning on using this vehicle for home deliveries, this is not the ideal truck for you.

Modifications

As stated previously, ensure the maintenance records are in order and the engine has been kept as stock as possible. Make sure the truck hasn’t been running any power adders. Since squeezing power out of these robust durable engines is so easy, some of the popular power modifications to look out for are any of the following:

  • Aftermarket Programmer / Custom Tune
  • Upgraded Cams
  • Improved Manifolds
  • Bigger Fuel injectors
  • Turbo Installs

IF the truck has been running with any of the above mentioned modification for extended periods of time, it would be wise to steer clear. This will purely be a judgment call on your part. These engines can make really big power with very few mods so depending on how much demand has been placed on the engine as well as the mileage, will be your determining factors here.

Let’s look at the stock power figures are on these engines.

RAM 6.7 Cummins Specs

The Ram truck division was spun off from the Chrysler in 2010 to better the brand name and identify themselves more clearly with potential customers.  These rugged, durable, robust 6.7L engines are best suited for towing since this 6.7 can effortlessly take care of your towing requirements. It provides impressive torque ratings for outstanding towing capability, without compromising on fuel efficiency. Equipped with a sophisticated transmission, the Corporate 68RFE six-speed automatic is a, multi-range, electronically controlled transmission. It features responsive performance and low noise, vibration, and harshness while driving.

Let’s take a look at the impressive performance figures:

Manufacturer:Cummins Inc
Engine Displacement:6.7L, 409 cubic inches
Cylinder Configuration:Inline 6 cylinder diesel
Bore x Stroke:4.21 in x 4.88 in
Horsepower:350 hp @ 3,013 rpm (intro)
385 hp @ 2,800 rpm (2016 – 2018 MY, H.O. model)
Torque:650 lb-ft @ 1,600 rpm (intro)
900 lb-ft @ 1,700 rpm (2016 – 2017 MY, H.O model)
930 lb-ft @ 1,700 rpm (2018 MY, H.O model)
Engine Weight:1050 lbs (dry)
Max Towing Capacity21,560 lbs
Max Payload Capacity5,730 lbs

User Experience

Mileage should not be your main concern when it comes to these 6.7 Cummins Rams. Many owners will admit to purchasing clean, reliable, high mileage Rams without major issues. Obviously, if you can afford a lower mileage truck, then why not, however, any vehicle will eventually need expensive repairs, including things like front end suspension work

Let’s see what one owner had to say

Owner Experience

I daily drive an 2008 6.7 Ram. Well it is a 2007.5 so the first models with the 6.7. I deleted it at 30k and haven’t had a single issue with the motor. Currently have 225k. I run it on 170hp tune unless I’m towing to get the best fuel mileage, just have to keep the foot out of it! The 68rfe did give up on me about 190k but I was not so easy on it for a few years right after I deleted it. IMO you can’t get a more dependable motor than the I6. (Once deleted)

https://www.reddit.com/user/dirtpoor1234

Deleted vs Stock

All modern diesel trucks are equipped with devices and components to make them friendlier for the environment and minimize the impact of pollution as much as possible. For this reason they are equipped with DPF (Down Pipe Filters), EGR (Exhaust Gas Recirculation) valves, and catalytic convertors. The downside to all these are they eventually get clogged up and slowly chock the engine’s performance. Needless to say, deleted trucks are a common thing and there’s the age old debate of which lasts longer, deleted truck or stock trucks.

There is no concrete evidence to support the theory that a deleted truck lasts longer. Many will have you believe that a Cummins 6.7 emissions system is trouble free till about 200-250, 000 miles. You can expect the DPF to start giving issues around that point once it starts to not regenerate. The regeneration process is necessary to reduce the accumulation of soot build-up on the DPF walls. Once this fails to happen, your will get engine error codes and limp mode issues to protect the engine.

Owners have reported DPF failures from around 200k miles and opted for a delete. Many trucks then continued on to well over 300, 000 trouble-free miles thereafter.

Cummins High Mileage Club

Cummins has an exclusive membership for owners with Cummins racking up over 100 000 miles or more. The Cummins High Mileage Club for Turbo Diesel owners is a special club created to recognize all the miles/kilometers our customers have driven with their Cummins Turbo Diesels. Cute!

6.7 Cummins at 100k Miles

RAM claims the DPF should be good for at least 100K miles. After which it needs replacement.  Depending on how close you are to that figure, you might be in for a replacement or a delete, depending on which side of the fence you’re on.  You might get away with higher, depending on the kind of driving the truck was exposed to.

I had 137,000 miles on my ‘dually’ before I did any mods. That was towing my 40′ equipment trailer everyday with 25-40K pounds behind the truck. I put that on in about 11 months.

https://www.cumminsforum.com/threads/how-many-miles-will-6-7-last-in-stock-condition.142428/

Other common components to look out for when you hit the 100k mile mark are but not limited to:

  • NOX sensors
  • DPF Filters

6.7 Cummins at 200k Miles

If you can find a clean example with 200k miles on the clock  make sure to inspect the undercarriage, frame, axles and all fluids i.e brake, oil and water. Forget about the mileage for a while and make sure to inspect the frame of the truck around all the holes in the frame for rust.  Trucks that has been regularly exposed to salt and snow will suffer from frame rot and undercarriage rust.

At 200k miles you can expect to spend some cash on maintenance issues. Do your due-diligence, but don’t let high mileage scare you.

A few items that needs to be inspected at 200k miles are:

  • White smoke on startup is a sign of injector wear.
  • Oil leaks
  • Excessive Blow by
  • Water Leaks
  • Diesel odor in the oil
  • Freshly painted undercarriage could be an attempt to hide something more serious.
  • Transmission issues.
  • Test the 4WD system thoroughly

Resources

Conclusion

The 6.7 Cummins engine is a decent improvement over the 6.4 with all the previous niggles rectified. The 6.7 is more like 6.0 in that you can do most things just fine without pulling the cab. The power is fantastic and most reliability issues have been rectified. At around 200K expect the emissions system to start causing hassles. Otherwise a fantastic engine with a good reputation for reliability.

Jade C.

4-Wheel drives and off-road driving techniques has been my passion for over 20 years. Here we strive to provide the most accurate, up-to-date, information about the functionality, common faults and latest technology built into most 4 Wheel Drives.

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