2017 Mercedes-Benz C 300 Fuel system Problems

The contact owns a 2017 Mercedes-Benz C300. While driving at approximately 15 mph, the contact observed smoke emanating from under the hood. The vehicle was driven to her work location and parked. Upon exiting the vehicle and opening the hood, she observed orange flames coming from the engine compartment. A parking attendant extinguished the fire, and a police and/or fire report was filed. The vehicle was towed to a dealer and diagnosed with a fuel line leak that caused the engine harness to come apart. The leaking fuel hose from the high-pressure fuel pump caused damage to the high-pressure pump, engine harness, vacuum transducer, and coolant feed line from the thermostat to the firewall. The following components needed replacement: high-pressure fuel pump, rubber fuel hose, engine harness, pressure transducer, and intake manifold. The vehicle was repaired. Five months later, the contact experienced another failure she believes was associated with the engine fire. While parked and attempting to start the vehicle, it did not start. The vehicle was towed to a dealer and diagnosed with a faulty starter that needed replacement. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 65,422.

NHTSA ID

11738037

Incident

Oct 29, 2025

Mileage

65,422 mi

strong evident fuel/ gas smell when driving and when the car is in park after driving.

NHTSA ID

11735746

Incident

May 1, 2024

UNKNOWN it was just one day I started my car and turned the A/C on and I started getting this strong gasoline smell. I went on like a saw there is a recall for this problem for the M274 engines.

NHTSA ID

11708103

Incident

Dec 25, 2025

Cabin smells heavily like fuel and has a check engine light possibly a fuel leak

NHTSA ID

11698322

Incident

Sep 25, 2025

small to much gas inside the cab and outside and bouth seatbelt doosent work corectly

NHTSA ID

11624452

Incident

Nov 3, 2024

my whole entire car smells like gas. I cannot drive this car around because I will pass out and it is a safety hazard. There is a recall for this exact same issue, just not for my Vin number. I would like to get this done for my car, please.

NHTSA ID

11621009

Incident

Oct 19, 2024

Keep getting a code P052E! Changed the oil and code went away for a few days then came back. Looked into getting it fixed and it seems like Mercedes has known about this issue and hasn’t called for a recall on this piece of equipment! Very costly to fix and says it needs to be replaced every 30k to 50k miles! At around 1k to 3k to fix everytime that’s something they should recall

NHTSA ID

11609586

Incident

Aug 14, 2024

The contact owns a 2017 Mercedes-Benz C300. The contact stated while driving at an undisclosed speed, the check engine warning light was illuminated but then disappeared. The vehicle was taken to an independent mechanic to be diagnosed. The vehicle was diagnosed with a failed actuator. The contact was informed that an actuator needed to be replaced. The vehicle was not repaired. The contact was informed of NHTSA Campaign Number: 21V961000 (Fuel System, Gasoline) however, the VIN was not associated with the recall. The manufacturer was made aware of the failure and advised the contact to report the failure to the NHTSA Hotline. The failure mileage was approximately 100,000.

NHTSA ID

11588398

Incident

May 8, 2024

Mileage

100,000 mi

During cold starts the fuel injectors/clamps leak causing strong gasoline smell inside the cabin. After research online this is a common issue with W205 systems. I am beyond surprised this has not been investigated and reported as a safety recall as it can pose a fire hazard. Please investigate and Mercedes should be fixing this issue….

NHTSA ID

11566746

Incident

Dec 1, 2023

every winter this car will have a heavy smell of gas in the engine and the cabin, after driving it for around 15 minutes with the windows open in the cold it goes away. no problem in the summer time. My mechanic said it's a common problem with these cars.

NHTSA ID

11563051

Incident

Jan 1, 2024

There is a short rubber fuel line/hose in the engine compartment that is attached with compression clamps; the hose connects the fuel line from the gas tank to the high pressure fuel pump. When it gets cold outside (below ~40 degrees Fahrenheit) the clamps loosen a bit and the hose will leak gas The entire interior smells like gasoline, really bad.

NHTSA ID

11560813

Incident

Oct 31, 2023

code p052e came on randomly.

NHTSA ID

11559554

Incident

Dec 11, 2023

I have a 2017 C 300 and it smells like gas when I turn my heat/ac on. I contacted Mercedes to see if there was a recall as this is a huge issue with many customers but Mercedes offered no assistance. The smell of gas is very dangerous and I think it's unfair to the customers that Mercedes has known about this problem but chose to do nothing.

NHTSA ID

11552831

Incident

Oct 31, 2023

My engine light comes on intermittently for days or weeks at a time. Code is P052E indicating an issue with the PCV valve. I'm waiting to replace the part.

NHTSA ID

11546465

Incident

Aug 9, 2023

My Mercedes Benz stopped working. The mechanic shared it involves the: fault valve for crankcase ventilation has malfunction.

NHTSA ID

11535656

Incident

Jul 27, 2023

I got a check engine lite and the code said positive crankcase ventilation regulator valve. While doing research I am finding out that this is a very common problem on these cars, and very expensive to fix, I’ve never even heard of this problem happening to other cars. I think a recall is in order, thank you

NHTSA ID

11532311

Incident

Jul 10, 2023

Code PO52E

NHTSA ID

11531076

Incident

Jun 13, 2023

The valve for crankcase ventilation code P052E71 is not under emission warranty WHY ? 45K car and is not working and it will not pass emission test

NHTSA ID

11517082

Incident

Apr 13, 2023

I have a mercedes c300 2017 and recently I was driving my car and the check engine light came on all of a sudden so I took it to my local shop to diagnose it they told me it was the PCV valve, so I called mercedes and they’re telling me that this is not covered and of course my warranty is no longer covered I have about 63k miles on the car. Mercedes is saying they don’t have a recall for this but I’ve googled around and multiple people are saying the same issue happened to them around the 55-65k range. It’s super frustrating that this doesn’t flag a recall.

NHTSA ID

11509860

Incident

Feb 24, 2023

My preowned vehicle has a strong gas odor in the cabin while operating. I don’t see any safety recalls but I did read online that a class action lawsuit proved my model may have faulty fuel parts causing seepage and the watranty is extended to 10yr/120k miles. I have scheduled maintenance this week but would like to be certain the warranty will cover this. Thank you.

NHTSA ID

11506962

Incident

Feb 3, 2023

I purchased my 2017 C300 class Mercedes-Benz ("MB") in May 2021 from a used car dealership in Mobile, AL. At that time it had 36,000 miles. Less than 2 years later, on or about 12/15/22, as I was driving, the MB suddenly and without warning began to vibrate violently and immediately lost power. The car had @54,000 miles on it. I routinely drive interstate to and from work and had just gotten off of the interstate. I was lucky that I was driving at a low speed when this happened; otherwise, a serious accident could have resulted. I took it to the local MB dealership which told me that the car failed a compression test in the #1 cylinder and that the engine would have to be replaced. Subsequent research on the cause of this total engine failure with low mileage revealed that this engine has a chronic piston defect that damages the #1 cylinder, causing it to lose compression, and that MB has known about the defect for many years, an issued an internal bulletin about it. MB has not alerted the public nor instigated a recall. I was not informed by MB at any time that the C300 class engine had a chronic piston defect that would damage the #1 cylinder which would, in turn, cause the engine to lose power and the vehicle to vibrate and shake, creating a dangerous diving condition under all circumstances, but especially if the car was being driven at speed on a federal interstate highway. Despite demands by me and others, MB refuses to responsibly address the issue. The driving public is, and remains, clearly, in great risk of harm due to this defective engine and associated power train issues. It is patently unreasonable for MB to produce and market such a unsafe, dangerous and defective product that poses an unreasonable risk of harm to its customers and others when being used as it was intended. I understand that the NHTSA has opened an investigation on this defect and wish for my voice to be heard on it. Please contact me [XXX] for further details. INFORMATION Redacted PURSUANT TO THE FREEDOM OF INFORMATION A

NHTSA ID

11500998

Incident

Dec 15, 2022

Please see attached letter: [XXX] Mercedes Benz Crankcase Valve Claim.pdf, repair estimate and other correspondence from Mercedes-Benz. This is an well-known issue where there is a gas lead from the engine where Mercedes insists doesn't pose a safety issue. During cold starts there is a smell of gas in the cabin and this is prevalent in colder climates like New England. Mercedes should make cars for all markets that are safe. INFORMATION Redacted PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6).

NHTSA ID

11484931

Incident

Apr 10, 2022

Diagnosis code P052E PCV regulator valve replacement/crankcase replacement. Dealership does not want to acknowledge code while car was under warranty despite proof that it existed when check engine was diagnosed. Now code keeps coming back with check engine light on dashboard. To replace part, the engine has to be taken down since the crankcase is inside the engine. This is a malfunction during assembly/manufacturing, it is impossible to damage part while under usage. Mercedes Benz should be held responsible for part replacement and labor. I urge you to investigate this matter with other clients and ask the manufacturer to replace part and pay for labor.

NHTSA ID

11471458

Incident

Apr 12, 2022

At approximately 26,500 miles of use, the check engine light came on in my Mercedes Benz C300. I brought the vehicle to the dealership and they informed me that the diagnosis was a crankcase vent valve malfunction. The MB fault code is P52E71. After paying Mercedes to fix the issue, I found forums on the internet where many other MB owners reported the same issue at around the same mileage. Being that this seems to be a common malfunction with the C300, I believe that it should be considered as a recall issue. I don't know what could have happened if I didn't service the vehicle, but any engine issue is dangerous while a vehicle is in motion.

NHTSA ID

11461236

Incident

Apr 10, 2022

When starting the car in the morning there is fuel smell that gets into the cabin. Additionally, as the car is idle during the drive, the smell of fuel is very obvious. Windows have to be rolled down to avoid the smell

NHTSA ID

11453550

Incident

Feb 1, 2022