The engine cam and lifters are bad. Engine started knocking with only 30,000 miles. Had to have lifters and cam replaced
2021 RAM 2500 engine problems
severe 13 complaints filed with NHTSA · avg repair $3,100 · see engine across all vehicles →
Complaints
13
Recalls
0
Avg fix
$3,100
1fire
The failure pattern owners describe
Owners of the 2021 RAM 2500 describe a range of engine and powertrain failures across this cluster. The most severe and recurrent complaint involves premature failure of the camshaft and lifters, primarily on 6.7L Cummins engines—one owner reported three separate lifter failures, with the latest allowing metal debris into the lubrication system and damaging crankshaft bearings. The ticking and knocking noises owners cite suggest bearing wear from contamination.
Several owners report uncontrolled acceleration under different scenarios: one experienced cruise-control-like acceleration that stopped only after powering down; another encounters aggressive RPM climbs and acceleration cycles (11–25 mph) when engine-braking downhill, forcing constant brake use. Check engine lights appear intermittently and clear before dealers can diagnose.
Other critical failures include an engine fire during startup (vehicle totaled in 10 minutes), a cracked EGR cooler leaking coolant with fire risk (same part across all model years but recall not issued for this truck), and cooling system gasket failure spraying coolant onto the intake. An independent ASE mechanic noted this cooling issue occurs across multiple RAM trucks. DEF tank sensors fail repeatedly—one owner's replacement failed again 14 months later at a cost exceeding $963. Transmission whining during gear shifts persisted even after FCA-approved part replacement, and one owner received a 15-inch replacement dipstick unsuitable for checking transmission fluid after a transmission recall.
Same RAM 2500 engine reports on nearby years: 2018 · 2019 · 2020
Failure modes owners describe
Camshaft and lifter failure
Premature failure of camshaft and lifters, often recurring after dealer replacement. Metal debris from failed components contaminates the oil system, causing secondary damage to crankshaft bearings. Owners report loud ticking or knocking noise from the engine. This failure mode is reported primarily on 6.7L Cummins engines in 2019+ RAM 2500/3500/4500/5500 models.
When: 30,000 miles and beyond; one owner experienced three failures requiring multiple repairs
Symptoms owners cite: loud ticking noise from engine; knocking noise; metal particles in oil; engine knock at operating temperature; tapping noise after warm-up
Codes mentioned: P0302
Repairs/costs cited: Dealer replaced camshaft and lifters multiple times at customer request; owners report dealers continue replacing with same flawed parts without addressing secondary engine damage
Uncontrolled acceleration / engine runaway
Vehicle accelerates on its own without driver input, often triggered by terrain changes or gear selection. In one case, truck accelerated as if on cruise control while owner reported cruise control unavailable; in another, engine RPMs spike and truck accelerates aggressively when in first gear on downhill grades, cycling between 21-25 mph and 11 mph regardless of brake application.
When: Intermittent; one owner experienced two occurrences; another reports reproducible on steep descents
Symptoms owners cite: vehicle accelerates without throttle input; high RPM climb on downhill in first gear; cruise control shows unavailable message; check engine light illuminates intermittently; truck reaches 21-25 mph then cycles down to 11 mph and accelerates again
Repairs/costs cited: Dealers unable to reproduce; check engine light clears before diagnostic scan completed; one dealership claimed behavior is normal
DEF tank sensor failure
Diesel emissions fluid tank sensor repeatedly fails, triggering check engine light. Owner reports sensor failed again 14 months after dealer replacement under warranty, suggesting the replacement part is defective or installation is flawed.
When: Recurring: first failure at unknown mileage, second failure 14 months after repair
Symptoms owners cite: check engine light illumination; sensor burns out
Repairs/costs cited: Dealer diagnosed as burned out and replaced part; repair cost over $963; same failure recurred within 14 months
Engine fire
Vehicle caught fire immediately after starting, with fire smell and smoke visible from engine compartment. Fire was catastrophic, totaling the vehicle within 10 minutes.
When: During engine startup
Symptoms owners cite: fire smell in cab upon starting; smoke from engine compartment; engine fire
Repairs/costs cited: Vehicle totaled; no repair attempted
EGR cooler failure / coolant leak
EGR cooler develops cracks and leaks coolant into the engine, creating burning smell and fire hazard. Owner reports all model years of this truck have the same part and part number, and all have experienced the same failure. Ram has recalled the part for other model years but not this specific vehicle.
Symptoms owners cite: cracked EGR cooler; coolant leak from cooler; burning coolant smell; potential fire risk
Repairs/costs cited: Dealer refusing to repair under warranty; owner reports same part and part number used across all model years
Recalls/TSBs owners mention: Ram has recalled this issue for other model years but has not issued recall for this vehicle; dealership suggested owner contact NTSB regarding recall
Cooling system gasket failure
Cooling system gaskets fail, spraying coolant across the intake manifold. One owner reports this is a multiple-vehicle issue among RAM trucks seen by independent ASE mechanics. Symptom initially presents as one-sided heater malfunction.
Symptoms owners cite: driver-side heater not functioning while passenger side heats normally; coolant spray onto intake manifold; coolant leak from failed gaskets
Repairs/costs cited: Independent ASE mechanic identified as cooling system gasket failure; dealer diagnosis not documented
Transmission whining noise on gear shift
Transmission produces whining noise during gear shifts under acceleration. Owner has returned to dealership four times for the issue; FCA approved repair of a small transmission part, which did not resolve the problem.
When: During acceleration and gear shifting
Symptoms owners cite: whining noise during transmission gear shifts; noise occurs under acceleration
Repairs/costs cited: FCA approved replacement of a small transmission part; repair unsuccessful
Recalls/TSBs owners mention: FCA approved repair of transmission component
Loss of motive power / drive power dropout
Vehicle loses all motive power while driving at various speeds. Dealer diagnosed ECM (engine control module) software issue and performed ECM update, but the failure recurred.
When: 37,510 miles
Symptoms owners cite: loss of motive power while driving at various speeds; repeated failure after ECM update
Repairs/costs cited: ECM was updated by dealer
Recalls/TSBs owners mention: Manufacturer was notified of failure
Dipstick change after transmission recall
Following repair under NHTSA Campaign 22V835000, transmission dipstick was replaced with a 15-inch unit instead of the original 44-inch dipstick. The new dipstick is not intended for checking transmission fluid level, leaving owner unable to monitor transmission fluid without dealer assistance.
When: Detected at 42,000 miles after transmission recall repair
Symptoms owners cite: shorter replacement dipstick received; dipstick not suitable for transmission fluid checking
Repairs/costs cited: Replacement dipstick is 15 inches instead of 44 inches; marked as not intended for transmission fluid level check
Recalls/TSBs owners mention: Manufacturer advised owner to take vehicle to dealer for fluid level checks; no explanation provided for change
Synthesized from 13 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 3 most recent
August of 2023 I took my truck in for a check engine light. The dealership diagnosed it and said my def tank senor is turning on the check engine light. They repaired it, when I picked up the truck they told me that "it was burnt out" and replaced the part. Now 14 months later it's having the same issue. Wondering if other ram 2500 owners are having this same issue and if it is a repetitive…
I recently bought this truck used from a Ford dealership. The next day when I was taking my wife for a short drive. I noticed the engine light was on the dash display. I the same time the truck started accelerating Like it was on cruise control and returning to a higher speed. The cruse control was not set when I tried to access the cruse control I would get the message that it was unavailable at…
Had engine trouble with your 2021 RAM 2500?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the engine problem on the 2021 RAM 2500?
It's a meaningful issue. 13 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $3,100.
At what mileage does the engine typically fail?
Based on the 13 complaints filed, engine issues most often appear around 39,755 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to engine?
No active recalls currently cover engine issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2021/RAM/2500.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.