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2021 Ram 3500 engine problems

13 complaints (21% of all complaints for this car).

owner complaints
13
of this car's complaints
21%
crashes
0
recalls
0

Which part fails

Owners did not name a specific part.

At what mileage

Complaints by mileage at the time of the problem.

0k-25k
25k-50k
50k-75k
75k-100k
100k-125k
125k-150k
150k-175k
175k-200k
200k+

Ram 3500 engine problems in other years

2007201520202026

Related recalls

No recalls on record for this model year.

What 2021 Ram 3500 owners say

Most recent owner complaints, unedited.

Filed Jun 1, 2026 · Driver assistance, Engine · WA

The contact owns a 2021 Ram 3500 . The contact received notification of the federal safety agency Campaign Numbers: 25V720000 (Engine and Engine Cooling) and 25V552000 (Back Over Prevention) however, the part to do the recall repair was not yet available. The dealer was contacted. The vehicle was not diagnosed or repaired. The dealer confirmed that the remedy parts were not yet available and were on backordered. The manufacturer was made aware of the issue. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The contact had not experienced a failure.

Filed Mar 25, 2026 · Driver assistance, Engine · NY

The contact owns a 2021 Ram 3500. The contact received notification of the federal safety agency Campaign Number: 25V552000 (Back Over Prevention) and 25V720000 (Engine and Engine Cooling); however, the part to do the recall repair was not yet available. The local dealer was contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The contact had not experienced a failure.

Filed Nov 19, 2025 · Electrical, Engine · PA

While driving my truck I noticed my mpg gauge was showing 0 mpg. Then I realized my "miles to go" gauge was reading "low" even though I had plenty of fuel in the tank and my fuel gauge was showing 3/4 full. Even though I use my truck as a commercial vehicle, and drive coast to coast, I was luckily only a couple hours from home, so I kept driving to try to make it home. I did make it home, but during that time, my "check engine light came on along with my "low fuel warning" light. I also realized during that time that my odometer had stopped working. It wasn't showing any numbers at all. When I got home, I checked online to see if anyone else had heard of this problem, or how to fix it. That's when I realized just how common this problem is. Even though my truck is used in the US and my mileage is calculated in miles, the odometer is programmed to stop working at 1,000,000 kilometers, which is 621,369 miles. Who would know or expect this to happen? I called several independent garages, all of which refused to attempt to fix an odometer problem because of the legal implications. I then called several Ram dealers who all told me they had never heard of this and would have to call FCA for advice on how to fix it. After two days of waiting, my local dealer called me back and said they could give me an appt a week later to diagnose the problem with my truck. They said FCA knows about the problem, but to fix it, it has to have a new gauge cluster installed. Nobody I talked to was able to tell me if the truck was safe to drive or why Ram wasn't warning owners of this problem when their trucks reached such an odd number of miles. When they replace the odometer, it will start over again at 0 miles and a sticker in the door jamb stating that the odometer was replaced at 621,369 miles, as if anyone would think to look in the door jamb for this sticker. The reason so few other drivers are going through this problem is because they are buying an OBD reader and resetting it.

Filed Nov 5, 2025 · Engine · 99,000 miles · TX · fire

The contact filed the complaint on behalf of the customer, who was the owner of a 2021 Ram 3500. The contact stated that while the owner was driving at an undisclosed speed, the vehicle caught on fire. No warning lights were illuminated. The owner informed the contact that the fire came from the engine bay. The fire department arrived and extinguished the fire. A police report was filed. The vehicle was taken to a local tow yard. The vehicle was later towed to the independent mechanic. No injuries were sustained. In addition, the contact stated that the transmission was replaced by an independent mechanic. The failure occurred the following day after the vehicle was released by the independent mechanic. In addition, the owner of the vehicle had received a recall notification the federal safety agency Campaign Number: 23V060000 (Electrical System). The manufacturer was not made aware of the failure. The failure mileage was approximately 99,000.

Filed Aug 8, 2025 · Brakes, Engine · OR

Vehicle died in a busy intersection coming off the freeway. Light flashed that indicated it was an issue with the electronic throttle control. The safety of myself and others was put at risk due to the posted speed of the road and multiple lanes from 4 directions. I had to remain in my vehicle to make sure I was not hit by another vehicle and due to the vehicle issue, I was impeding traffic. Lithia Dodge of Grants Pass, OR stated they could not make an appt for the vehicle to get looked at for 2 weeks out, scheduled 8/22/25. Dealership seems to think this is not an issue with safety and this issue can occur while the vehicle is in motion which is a huge safety issue. No warning lights flashed before the first one indicating the vehicle would shut down/lose all power.

Filed Aug 6, 2025 · Engine · CA

Failure of hydraulic lifters and camshaft in Cummins 6.7 liter diesel engine of 2021 RAM 3500. Engine exhibited significant ticking noise and the engine does not work properly, putting the safety of driver and passengers in vehicle at risk. Vehicle is not driveable. This issue has been confirmed by the RAM dealership in Livingston, Montana. The 2021 RAM 3500 truck has been sitting at the RAM dealership for the past seven weeks awaiting parts and a fix that RAM trucks is still trying to figure out. Apparently, this has become a common problem with the RAM Cummins 6.7 liter diesels from model years 2019 through current 2025 models, including 2021. The RAM dealership in Livingston, Montana has five separate RAM Cummins 6.7 liter diesel trucks with the same issue awaiting parts and a fix from RAM.

Filed Dec 25, 2024 · Engine · ID

Hydraulic roller lifter failure.

Filed Jun 21, 2024 · Engine · 190,000 miles · CA

The contact owns a 2021 Ram 3500. The contact stated while driving at an undisclosed speed, the engine temperature gauge became extremely elevated. The contact pulled over to the side of the road and an independent mechanic briefly inspected the vehicle and informed the contact to refill the coolant reservoir. The contact refilled the reservoir and after driving for approximately thirteen minutes, the failure reoccurred. The vehicle was towed to an independent mechanic where it was diagnosed that the EGR cooler and EGR valve needed to be replaced. The vehicle was not repaired. The contact related the failure with Emissions Recall: VB6 (Diesel Engine Calibration); however, the vehicle was not included. The manufacturer was not made aware of the failure. The failure mileage was approximately 190,000.

Filed May 14, 2024 · Engine · CO

There exist a defect which is common through multiple years with RAM that have the Cummins 6.7L diesel engine. The problem is the heater bolt in intake system. When this fails it falls into intake and proceeds into piston which requires engine rebuild. Unfortunately the same part is put back in causing repeat. Solution Banks Monster Ram Intake system. Many, many owners over years have experienced loss of vehicle in both new and older models. Engine lock up can cause loss of steering and worse on highways.

Filed Apr 26, 2024 · Engine · TX

Catastrophic lifter failure. Was able to safely deliver vehicle to dealership service department. If not handled properly, engine failure could occur while driving and hurt/kill someone.

Questions about the 2021 Ram 3500 engine

Does the 2021 Ram 3500 have engine problems?

Owners have filed 13 complaints about the engine of the 2021 Ram 3500, 21% of all its complaints.

At what mileage do 2021 Ram 3500 engine problems start?

Not enough complaints include the mileage to tell.

Is there a recall for the 2021 Ram 3500 engine?

There is no recall for this problem on this model year.

Other 2021 Ram 3500 problems

Electrical 17Transmission 11Wheels 7Brakes 6Body 5Fuel system 5Driver assistance 4Lights 3Tires 3Suspension 2Acceleration 1Seat belts 1Seats 1Steering 1Visibility 1

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