What 584 owners told NHTSA about the 2012 Mercedes-benz C-class Coupe

The model/year Mercedes-Benz are well known for experiencing this/these particular issues. My research has shown that these year/make/model vehicles are experiencing the same type of mechanical failures nationwide. The issues all relatively begin around 75,000 miles. I've only had my car 3 years putting 30000 on it hardly driven/cared for **Issue Found:** Oil was leaking onto the ignition coil and spark plug of cylinder 3. **Source of Leak:** Valve cover gasket failure. **Recommended Repairs:** - Replace the valve cover gasket (to halt the oil leak). - Replace spark plugs and ignition coil (which were contaminated/damaged by oil). **Relevance to Warranty:** The valve cover gasket is only covered if it fails as a result of an internally lubricated engine part causing damage. Ignition coils and spark plugs are maintenance items and are not covered by warranty plans. **Required Repairs (Identified Mechanical Issues)** - **Coolant Pipe Leak – $850** **Issue:** Coolant leaking from a pipe on the side of the cylinder head. **Relevance to Warranty:** Typically not covered unless it pertains to a failure in a covered system such as the water pump or cylinder head due to an internal breakdown. This is likely classified as an external plumbing component, which is not included. - **Oil Feed Line Leak – $600** **Issue:** Oil leaking from the side of the engine, traced back to the oil feed line. **Relevance to Warranty:** This is not typically covered unless the oil feed line is part of the oil pump system and has failed due to an internal issue (usually regarded as an external line). **Other Items Found (Worsening Issues)** - **Timing Chain Rattle / Cam Adjuster Noise – $6,000** -**Issue:** Rattling sound during startup. **Diagnosis:** Noise emanating from the timing chain and camshaft adjusters. **Relevance to Warranty:** This is covered under Secure Plus, as both the timing chain and camshaft adjusters are recognized as internally lubricated par

NHTSA ODI 11666448

Lost of drive power and the vehicle steering wheel locked on my mercedes from a damaged malfunctioning steering lock actuator module due to mechanical issues within the steering column such as bad steering wheel assembly, faulty steering lock module or issue with the wiring or other electrical components and the mercedes dealer is the only one who solves this issue no other mechanic in general. My safety was at risk due to I lost power and lost of front brakes due to bad sway bar assembly or components could of caused and accident when this happened on November 12, 2024 the problem dealership found during vehicle inspection was code 25464 they told me recommend to replace electric lock module and repair estimate was $2,829.78 and before I approved the the amount I told Mr Ivan Velasco service advisor that after they replace the module that if my vehicle was going to be working again and that if I was just going to make 1 payment of $2,829.78 then I would approved it so I did. Weeks later I got an email asking for more money they wanted another payment for $600 saying it needed a sensor that has something to do with the transmission because after replacing the new module the vehicle did not start up there was no type of communications nothing at all and I responded that I was not going to pay $600 more just cause they don't know what their doing because they promise me the car was going to work after they replace the module now that it did not want to crank up they found another issue that's their fault on not doing there job the right way and for telling lies yes their was flashing blue or red icon on my dashboard that look like a car and a lock would go on and off and it displayed a message saying The theft protection is activated. I want to know if I can get this issue approved and to be considered a recall can you please help I'm so frustrating and mad that they want more money when it's already so expensive please help I would of appreciate it thank you.

NHTSA ODI 11638949

vehicle sub-frame is cracked rusted corroded.

NHTSA ODI 11572697

The left rear weld of the subframe on my 2012 C300 4matic has rotted through and appears to be a manufacture's part defect. I found out about this issue from a brake inspection and told it is a safety concern, which Mercedes Benzes is aware of but has no recalls for the defect.

NHTSA ODI 11513818

My car’s left side rear subframe is cracked due to corrosion. I started hearing a weird noise a week ago, and my car suddenly veered to the left side when I pressed the brake. I almost crashed my car because the car moved to the left of the yellow line on the road. I searched about this issue on Google and found that many C-Class owners (W204 generation) are experiencing the same issue due to the design flaws/defects by Mercedes-Benz. Now I have to pay up to $10,000 for the repair that is due to a defective part. In other countries like the UK and South Korea, this issue is covered by Mercedes-Benz, but in the United States, it is not covered. The repair is done at owner’s expense. I fear driving now because my car steers to the left when I press the brake. The rear subframe must be recalled since this issue is now common to all C-Class models produced in 2008-2014, and if car accidents occur, many people can be killed. I almost crashed my car due to my rotten subframe. Please help.

NHTSA ODI 11509103

The contact owns a 2012 Mercedes-Benz C300. The contact stated that while the vehicle was receiving a routine maintenance, she was informed that the rear sub frame was rusted and had two holes. The vehicle was diagnosed that there was a transmission leak and the rear sub frame needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure but no additional assistance was provided. The failure mileage was approximately 88,000.

NHTSA ODI 11464082

I HAVE BEEN HAVING ISSUES WITH MY VEHICLE SINCE I PURCHASED IT. STARTING WITH ME NOT HAVING ENOUGH POWER FROM A START, IN AN ATTEMPT TO GAIN ENOUGH POWER TO DRIVE AT A SAFE SPEED FROM THE START, AS IF THE VEHICLE LAGS & NO MATTER THE GASOLINE OR SERVICE, THE PROBLEM NEVER CORRECTS. WHEN I'M TRYING TO GAIN SPEED TO MAINTAIN WITH THE FLOW OF TRAFFIC SAFELY THE VEHICLE LAGS NOTABLY BEFORE GAINING SPEED. I'M NOW HAVING TO REPLACE THE ENGINE BC THE OIL COOLANT HOSE BURST WHILE I WAS DRIVING ON THE HIGHWAY WITH MY CHILD IN THE CAR. MY CHECK ENGINE LIGHT ACTIVATED BUT THE ONLY NOTICE DISPLAYED ON THE DASH WAS THE ENGINE COOLANT WHEN IT WAS LOW. WHEN THE HOSE BURST WHILE I WAS DRIVING ABOUT 60MPH I HEARD A POP SOUND UNDER THE HOOD, SAW SMOKE COMING FROM THE EXHAUST, THEN A CLANKING NOISE UNDER THE HOOD THAT GOT LOUDER & LOUDER UNTIL I WAS ABLE TO PULL OFF OF THE HIGHWAY, & THEN I NOTICED A VERY LARGE AMOUNT OF OIL ON THE GROUND THAT LEFT A TRAIL ALONG THE GROUND FROM MY VEHICLE. THAT WAS VERY DANGEROUS AS MY VEHICLE LOST POWER DURING THAT INCIDENT. I'M TOLD BY THE MECHANIC, THE ENGINE HAS TO BE REPLACED. THIS HAPPENED WITHOUT A WARNING. THE MERCEDES BENZ IS SUPPOSED TO BE A SAFE & RELIABLE LUXURY VEHICLE & NOT A NIGHTMARE TO HAVE FOR THE OWNER.

NHTSA ODI 11385548

TL* THE CONTACT OWNS A 2012 MERCEDES BENZ C300. THE CONTACT STATED THAT WHEN THE VEHICLE WAS STARTED AND THE ACCELERATOR PEDAL WAS DEPRESSED, THE VEHICLE STALLED WITHOUT WARNING. THE CONTACT MENTIONED THAT THE FAILURE OCCURRED PERIODICALLY. THE VEHICLE WAS TAKING TO AN INDEPENDENT MECHANIC WHERE THE FAILURE COULD NOT BE DETERMINED. MERCEDES-BENZ OF ALEXANDRIA (200 S PICKETT ST, ALEXANDRIA, VA 22304 (703) 341-2100) AND MERCEDES-BENZ OF ANNAPOLIS (324 6TH ST, ANNAPOLIS, MD 21403 (888) 261-7620) WERE CONTACTED AND INFORMED THE CONTACT TO BRING THE VEHICLE IN FOR A DIAGNOSTIC TEST. THE VEHICLE WAS NOT TAKEN TO A DEALER FOR A DIAGNOSTIC TEST OR REPAIRS. THE MANUFACTURER WAS NOT MADE AWARE OF THE FAILURE. THE FAILURE MILEAGE WAS 135,000.

NHTSA ODI 11206447

I BOUGHT THE CERTIFIED CAR AT 50K AND AT 70K MILES, RIGHT AFTER THE WARRANTY ENDED - CHECK ENGINE LIGHT CAME ON AND THE DEALERSHIP SAID IT WILL COST $8K DUE TO CAMSHAFTS TO REPAIR!! THEY EVEN SUGGESTED THAT I SHOULD CONSIDER TRADING THE CAR IN! KEEP IN MIND I STILL OWE $28K SO THAT OPTION IS OUT! SINCE THEN THE CHECK ENGINE LIGHT STILL ON EVEN AFTER I GOT IT REPAIRED AT A LOCAL/AFFORDABLE MECHANIC AND IT'S ABOUT 110K MILEAGE AND THE ENGINE IS RATTLING AS IT RUNS. THIS IS MY 3RD BENZ AND THE FIRST 2 FAILED DUE TO THE TRANSMISSION FAILURE. I JUST CAN'T BELIEVE THESE GERMAN CARS CAUSE SO MANY PROBLEMS AND SO COSTLY TO REPAIR. WHAT HAPPEN TO YOU PAY FOR WHAT YOU GET!!! TODAY, WHILE I WAS DRIVING THE CAR JUST SLOWLY STOP AND THE ENGINE CUT OFF! AAA CAME TO CHECK AND IT'S NOT THE BATTERY SO WILL NEED TO GET TOWED. STILL OWE $10K LEFT- I DON'T KNOW WHAT TO DO! NO OTHER CAR TO DRIVE .

NHTSA ODI 11160631

GRADUALLY AS THE CAR IS ACCELERATING IT MAKES A TERRIBLE GRINDING NOISE AND SHAKES ALSO JERKS WHEN CHANGING GEARS, CONFIRMED IT IS A FAILED TRANSMISSION, THE CAR HAS HAD ALL THE APPROPRIATE MAINTENANCE JUST NOT AT A MB DEALER AND THERE IS A SERVICE BULLETIN ON THE TRANSMISSION JUST NOT OFFICIAL RECALL AND MERCEDES IS CLAIMING NO RESPONSIBILITY AS IT WAS NOT SERVICED AT MB DEALER SINCE 2014. CLEARLY THE SERVICE ANNOUNCEMENT IS RECOGNITION OF A PROBLEM

NHTSA ODI 10954830

THE CEL CAME ON AND THE ENGINE WAS HAVING A ROUGH START . I TOOK IT TO THE REPAIR SHOP AND AFTER USING THE STAR DIAGNOSTIC SYSTEM THE DIAGNOSES WAS CAMSHAFT ADJUSTERS IN FAILURE. THE REMEDY REPLACE THE CAMSHAFT ADJUSTERS. COST $3500.00. *TR

NHTSA ODI 10946355

THIS WAS NOT AN ACCIDENT, IT IS, IN MY OPINION, A POSSIBLE SAFETY PROBLEM WITH THE VEHICLE - TURBO LAG; THROTTLE LAG; TRANSMISSION LAG. I ALMOST HAD TWO ACCIDENTS DUE TO THE LAG PROBLEMS, AND HAVE ATTACHED A MORE DETAILED ANALYSIS FOR YOUR REVIEW. TURBO LAG: THIS IS THE TIME IT TAKES FOR THE CAR TO GO FROM ITS NATURALLY ASPIRATED POWER TO THE FULL POWER OF THE CAR AT FULL BOOST/ PEAK BOOST IS REACHED RELATIVELY LOW IN THE REVERSE RANGE, BUT IT IS NOT INSTANTANEOUS POWER LIKE A NATURALLY ASPIRATED ENGINE. THROTTLE LAG: THE DRIVE BY WIRE SYSTEM HAS A BIT OF LAG. UNDER CERTAIN CONDITIONS, I MEASURED IT AT .2 OF A SECOND OR SO. WHATEVER THE VALUE, THERE IS ALWAYS LAG THERE, AND WE ARE VERY SENSITIVE TO IT. HOWEVER, DRIVING INS MODE VS E MODE DOES MAKE SOMEWHAT OF A DIFFERENCE. NONETHELESS, THE CAR ALWAYS STARTS OUT IN E MODE WHEN I GET IN AND START THE CAR. WE DIDN'T PURCHASE THE CAR TO ALWAYS DRIVE IN S MODE. TRANSMISSION LAG: THIS I NOTICE SIGNIFICANTLY AND IT IS, IN MY OPINION, PROBABLY THE MOST ANNOYING TO ME. YOU'LL NOTICE THIS WHEN STOMPING THE PEDAL TO THE FLOOR AND THEN DOING THE WAIT... WAIT... WAIT.. DOWNSHIFT. EVEN IF THIS ENGINE WAS RUNNING ONLY ON ITS NATURALLY ASPIRATED FOUR CYLINDERS, THE TRANSMISSION SHOULD RESPOND IMMEDIATELY TO A SURE FOOTED STOMP TO THE FLOOR WITH THE QUICKNESS, AS DOES MY FOUR CYLINDER RAV-4. HOWEVER, THE MB C-250 DOES NOT! IN MY OPINION, YOU CAN RESET THE TCU ALL YOU WANT, THE DELAY WILL REMAIN.

NHTSA ODI 10481881