Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2016 Mercedes-Benz C300 owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2016 Mercedes-Benz C300. The contact stated that while at a stoplight, the energy saver START/STOP feature engaged, but the vehicle stalled and failed to restart. There were no warning lights illuminated. The vehicle was towed to an independent mechanic who determined that the START/STOP function failed to operate as designed. The mechanic informed the contact about NHTSA Campaign Number: 17V114000 (Electrical System, Engine and Engine Cooling). The local dealer was not contacted; however, the vehicle was not diagnosed or repaired. The manufacturer was not contacted. The failure mileage was approximately 56,000.
The contact owns a 2016 Mercedes-Benz C300. The contact stated that after turning off the vehicle and locking the doors; after a while, the vehicle would independently unlock the doors and then start up without driver input. The vehicle was taken to the dealer however, the mechanic was unable to determine the cause of the failure. The vehicle was not repaired. The manufacturer was not made aware of the failure. The approximate failure mileage was 43,000.
2016 MB 300 C, AWD at 87000 miles started giving gas fuel smell when parked in our garage after driving. I took to a local Foreign Car Repair facility and they found a fuel leak at the fuel injector pump. The mechanic changed the Fuel Injector Pump (Bosch) at a total cost of $745.31. Since the change in the pump, the smell has stopped and I feel safe. Who is responsible to reimburse this cost to me?
The contact owns a 2016 Mercedes-Benz C300. The contact stated he noticed an abnormal fume odor entering through the air vents of the vehicle. The contact self-diagnosed the vehicle as having a fuel leak from the fuel pump. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The manufacturer was not made aware of the failure. The failure mileage was approximately 83,000.
Around the 58,000 mile mark my check engine light on my 2016 Mercedes C300 4MATIC came on . I checked the gas cap, as that can set off the check engine light, and the check engine light went off the next day. 3 days later the check engine light comes on again, so I repeated the steps of taking the gas cap off and putting back on. The light did not go off the next day. 5 days later the light goes off again. This happened several times over a span of 2-3 weeks. I then take my car to be checked with an OBD-II Scanner. It read off every time the check engine light had been on, which was several times. The error code the scanner displayed was "P052E" and a description of "Positive Crankcase Ventilation Regulator Valve Performance". It was the same code multiple times. At this point I did a little research to see if this was something I could repair. …
My C300 MBZ, 2016 is experiencing the same symptoms as indicated in a recall, but my vehicle is not included in that recall. Camshaft: GENERAL REPAIR A cam is a rotating or sliding piece in a mechanical linkage used especially in transforming rotary motion into linear motion or vice versa. Cams act as a vital component to your automobile's engine. A camshaft is a shaft to which a cam is fastened or of which a cam forms an integral part. Camshafts provide power to the cams which are vital for basic engine operation. The cost of fixing this approximately $10,000 per Mercerdes dealer and estimate from Keyes Mercerdes. The Brief: Mercedes-Benz issued a recall for some model cars tied to a faulty drive shaft.T he problem not only can cause vehicles to lose power but may elevate crash risk, according to the National Traffic Safety Administration. …
My check engine light came on at about 68,800 miles. The OBD code shows that I need the Positive Crankcase Ventilation valve replaced. The repair for this is approximately $2,300 and requires about six hours of shop labor, and the part costing over $425. I've never known a PCV replacement on any vehicle to be more than $60, with the part itself being about $10-$20. Most times, the part can be simply cleaned and replaced. This is very disappointing. Especially given that the engine design, just two years prior, would have been less than $200 for the same repair, with part costing about $60. The vehicle does not show any symptoms of the part being blocked, as indicated in the code. There is no hesitation, loss a power or decline in fuel efficiency. However, the engine light cannot be turned off until the part is replaced. …
CHECK ENGINE LIGHT appeared on dash at approximately 72k miles. Had code read and diagnosed by certified mechanic and he had an active code P06DA00(this code signifies an electrical fault, open circuit, or high resistance in the circuit for the oil pump control valve on vehicles with two stage oil pump, which can lead to incorrect oil pressure, which can cause engine damage if not addressed). Vehicle was taken to Harriman Mercedes in New York. They did not acknowledge an active code but wanted to diagnose and repair a stored code for a small evap leak, which was rectified with a new gas cap. After prying about the P06DA00 code, they finally admitted it did have a stored code but to ignore it because it had something to do with domestic and foreign car engine computers issues. How do you ignore an active code with a potentially serious engine issue and told to ignore it. …
I bought the car with 51k miles . Engine failed at 71k miles , due to piston #1 cracking . Almost caused me to get rear ended on a busy street . I went to the dealership and they charged me $10250 to replace the engine with a remanned long block and they offered a 2 year warranty. 9 months, only 19k miles on "new motor" the "new" engine fails again ... same reason piston # 1 cracked failed suddenly on the highway and I had to push the car to safety to the emergency lane while cars where coming.. I went back to dealer demanding a replacement and told them this is a common occurrence and they refused to help me . I called corporate. They refused to help me saying I would have to purchase an engine for the second time out of pocket when it only lasted 9 months. This is a big fault in the m274 engine ... …
P052E - PCV Regulator Valve Performance: Actuator Stuck P06DA - Engine Oil Pressure Control Circuit/Open no sub type information My understanding is these are common issues and Mercedes and anyone who works on them know it is a common issue for all lines. I also have a broken sunroof that seems to be common on all lines. There are some recalls out for the sunroof but not for the C-Class C300, although all of the videos I have found match the same issues that were recalled on other models. The dealer confirmed these are known issues.
Engine complaints in other C300 years
Frequently asked questions
How common are engine problems on the 2016 Mercedes-Benz C300?
NHTSA has 94 complaints about the engine & cooling of the 2016 Mercedes-Benz C300, 33% of the model year's 289 complaints.
Is there a recall for 2016 Mercedes-Benz C300 engine problems?
No. NHTSA lists no engine & cooling recall for the 2016 Mercedes-Benz C300, though it has 13 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 2016 Mercedes-Benz C300 engine problems start?
Half of the complaints with a recorded mileage happened before about 29,000 miles, and 46% before 25,000 miles.
Is it dangerous?
Owners linked 0 crashes, 2 fires 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.