Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2014 Mercedes-Benz E350 owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2014 Mercedes-Benz E-350. The contact stated that while the vehicle was parked and occupied, the contact heard an abnormal rattling sound coming from the engine that lasted for approximately 3 seconds when first started. An independent mechanic was contacted. The vehicle was taken to an independent mechanic, and the contact was informed that the failure was a common issue, and that the vehicle operated as designed. The contact stated that the failure might be related to the timing chain or the lifters. The contact stated that there were no issues while driving the vehicle, only whenever the vehicle was first started. The contact stated that after the engine had warmed up to operating temperature, the sound was no longer heard. The vehicle was not repaired. The manufacturer was notified of the failure and advised the contact to report the failure to the NHTSA Hotline. …
I brought in my car to M1 Mercedes, Fremont, CA for service after "check engine" light was on and running rough on idle. I told them I started using ethanol (E85) fuel recently but my car is spec for that. The shop replaced spark plugs and ignition coils but the issue didn't go away. While the car is parked overnight at the shop garage, on Jun 21, 2022, around 11pm, the engine exploded. The incident was caught on camera by the shop. The intake manifold was blown open. The car was tolled to Fletcher Jones Mercedes Fremont, CA (authorized Mercedes dealer) for diagnostic. However, they didn't offer any solution or attempt to find out what caused the explosion. They offered to replace the intake manifold for $1200. I declined as I believe this is a serious safety issue. What happen if it explodes again? Since the cause of the explosion is not found and address. …
The camshaft adjuster failure. Though I'm told safety is not in immediate danger, it's a very expensive fix that can cause other issues if left unpaired. It began subtly with strange noises, hesitation during start-up, inconsistent performance. I take meticulous care of this vehicle. Regular service. Genuine parts. Always handled with care. And yet, here I am, facing a repair bill that is not only shocking, but unjust. Especially for this to be a common problem. Not to mention the potential for severe engine damage if left unresolved. I've since learned that I am not alone. Many loyal Mercedes owners have faced the same issue; often at relatively low mileage, with little to no warning. This is not an isolated defect. It is a systemic issue with significant implications, not just for the vehicle, but for the trust your customers place in your brand. …
Car was being driven at secondary road speed (~40MPH). Engine suddenly began to spudder and misfire terribly. Came to a stop light engine was idled roughly. Accelerated from stop, when check engine light turned on. Car went into limp MODE at a very dangerous rail road crossing and left turn intersection. Without acceleration, family was in danger of being hit by train and incoming traffic. Took car to Mercedes mechanic. Faulty parts were the Camshaft Position Solenoid valve, ignition cool. Short circuit in one part caused blown ignition fuse and cascading mechanical problems and safety risks. Repair cost so far is $1,100. Concern is the placement of the faulty part. It is exposed to high heat in the motor compartment and poses a fire hazard as well as a personal injury hazard to the occupants and driver.
My 2014 Mercedes started getting a fault light with multiple performance issues. Mercedes dealer where I can carry out my routine maintenance diagnosed the issue to the electrical harness being contaminated with engine oil and it needed to be replaced on the engine because of a known issue whereby oil from the upper camshaft sensors seep into the harness and makes its way to ECU and causes possible failure of the engine control, which could lead to shutting down or worse, incorrect engine timing which would lead to incorrect detonation at the compressors and subsequently engine failure at critical operational phase. This below link and attached document describes the issue well. [redacted]
Mercedes Benz had a previous recall Campaign # 2009100001 which affected vehicles until 2012 and mine is a 2014 model E350. It has the same issue with Engine severely misfiring and jerky on the road as if it is going to STOP IN THE MIDDLE OF FREEWAY while driving and cause a SAFETY RISK for my family and others on the road. Specific component is Oil leaks from transmission wiring harness and ECM connector. The leak is from camshaft hall sensors and transmission drain plug. Mercedes Benz dealer in Pleasanton, CA has confirmed the issue after I paid $218 for diagnosis.
I own a 2014 E350 mercedes benz the transmission was recalled a while back but long story short my car has all the same exact problems a lot of e350 owners are having with the conductor plate witch causes rough shifts between 1st and 3rd gear car went to Mercedes' for more testing now I've got a 13000 dollar estimate and problem is even though the vin doesn't show it was recalled for that reason the problem is spread world wide cuz my car only has 60000 miles and every one's Mercedes' is giving same exact problems not just mine so it has to be a recall
Motor mounts and transmission mounts continue to fail at intervals or 13,000 miles and again at 16,000 miles. Vibration of transmission is scary. Mercedes has replaced the mounts many times. They refuse to install new Transmission mount now after only 16,000 miles on the replacement. I have contacted MBUSA and they are telling me , they will not help with these substandard parts. Very well-known issue.
Issue with fuel injection for Benz E350 2014 2014 Mercedes-Benz E350 fuel injection issues often stem from faulty injectors causing misfires, often on Cylinder 5, or a recalled fuel feed line. Symptoms include rough idling, reduced gas mileage, stalling, and check engine lights (P0300-P0306 codes).
Engine camshaft position sensors are leaking oil which has "wicked" into the engine wiring harness and ECU. This is a common safety issue on this year and I would like to urge Mercedes to issue a recall as oil contamination within the electrical system can lead to a host of other safety concerns.
Engine complaints in other E350 years
Frequently asked questions
How common are engine problems on the 2014 Mercedes-Benz E350?
NHTSA has 21 complaints about the engine & cooling of the 2014 Mercedes-Benz E350, 8% of the model year's 278 complaints.
Is there a recall for 2014 Mercedes-Benz E350 engine problems?
No. NHTSA lists no engine & cooling recall for the 2014 Mercedes-Benz E350, though it has 8 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2014 Mercedes-Benz E350 engine problems start?
Half of the complaints with a recorded mileage happened before about 29,000 miles, and 45% before 25,000 miles.
Is it dangerous?
Owners linked 1 crash, 1 fire and 0 injuries to engine & cooling problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.