69 of the 333 complaints about the 2012 Mercedes Benz C300 are about the suspension — 21% of everything reported for this model year. Half of the failures with a mileage on record happened before 121,218 miles.
69
Complaints
0
Crashes
0
Fires
0
Injuries
Filed with NHTSA, in their own words.
SUSPENSION
I have a rust free, relatively lower mileage car I bought for my teen daughter. Despite being such a clean car the rear subframe has rusted and rear suspension has broke off while driving, hitting the fuel tank and is unstable. We avoided an accident but the car is not drivable.
NHTSA complaint #11732281 — an unverified report by a vehicle owner.
SUSPENSION
Mercedes of Danbury replaced the rear sub frame CODE 3441 47, since my mechanic (Newtown Auto Repair) told me that the Front subframe is in real bad shape, rotten/rusted, that it is dangerous to drive the car in this condition since the wheel and steering components are part and attached to it, the car would be out of control and all over the road any of these components fail and pull / brake away from the rusted out Sub Frame. When I brought the car in was under the impression that Mercedes Benz would replace front and back Sub Frames. But now they informed me of only recall on rear subframe, rear subframe will let go wheels will collapse, front controls the car and failing could kill people and total the car. frames.
NHTSA complaint #11701264 — an unverified report by a vehicle owner.
SUSPENSION
Rear subframe crossmember rotting, needs replacement. It seems to be a common problem with this vehicle and the assumption by most professional is that it a faulty part supplied by a third party to Mercedes. The rest of the cars undercarriage is pristine, making me wonder why just this one part would rust out.
NHTSA complaint #11674095 — an unverified report by a vehicle owner.
SUSPENSION
Took the car in for an oil change and asked them to look at the brakes and rear as there was a strange noise. Vehicle was inspected and found the entire subframe is rotted. Was advised this is a common problem with Mercedes and there were some recalls. Unfortunately no open recall on this vehicle and it is now not driveable as this is a safety risk. Car has been driven 60 miles/day for the past 3 months and could have had serious consequences.
NHTSA complaint #11639290 — an unverified report by a vehicle owner.
SUSPENSION
The contact owns a 2012 Mercedes Benz C300. The contact stated that while driving at various speeds, the vehicle would shake without warning. The vehicle was taken to an independent mechanic for a tire rotation; while there, the mechanic discovered severe corrosion on the vehicle's subframe and the contact was advised to no longer drive the vehicle. The manufacturer was notified of the failure. The vehicle had yet to be repaired. The failure mileage was approximately 160,000. The VIN was not available.
NHTSA complaint #11635199 — an unverified report by a vehicle owner.
SUSPENSION
The subframe has developed extensive rust and corrosion, which I believe is a result of faulty manufacturing. This corrosion has severely compromised the structural integrity of the subframe, posing a serious safety risk. The corrosion appears to be inherent to the materials or design used in the manufacturing process, leading to the rapid deterioration of the subframe. There are also no warning lights or failure indicators for this issue. As a result, the subframe is at risk of collapsing, which could cause catastrophic failure of the vehicle's suspension and steering systems. This situation creates an immediate danger to both the occupants of the vehicle and others on the road.
NHTSA complaint #11612045 — an unverified report by a vehicle owner.
SUSPENSION
My 2012 c300 has a rotted rear subframe making the car not able to be driven. It has major ,life threatening, costly damage and this issue already has a recall all over the world but not in the United States. If I can get the assistance to pay this repair, it will be gladly appreciated.
NHTSA complaint #11602805 — an unverified report by a vehicle owner.
SUSPENSION
Took my car for a doorknob repair and was told the whole subframe is rotted. They told me not to drive the car on the highway. The car brakes very hard to the right and always goes right while making cranking noises. Car feels very unsafe. I paid a lot of money for this and own a 2012 c300 4matic.
NHTSA complaint #11592433 — an unverified report by a vehicle owner.
SUSPENSION
Subframe rusted and broke. It is available for inspection. Burlington Mercedes inspected the vehicle and told me it was not safe to drive. Mercedes-Benz USA is aware of the problem. They issued a letter extending the warranty covering only the subframe to twenty years and unlimited miles. Burlington Mercedes refused to do the subframe replacement without installing all new arms, which are currently not damaged. The cost to install all new arms is $2826.54. Mercedes-Benz USA is offering a warranty extension that their dealerships refuse to honor. This needs to be turned into a recall instead of a warranty extension. This subframe issue is dangerous. It affects Mercedes vehicles dating back to 2005 and encompasses many of their models including: SLK- Class, CLS-Class, SL-Class C-Class Sedan/Coupe, GLK-Class E-Class Sedan/Wagon, E-Class Coupe/Cabrio
NHTSA complaint #11588793 — an unverified report by a vehicle owner.
SUSPENSION
The contact owns a 2012 Mercedes-Benz C300. The contact stated while driving at an undisclosed speed, he heard an abnormal sound coming from the rear of the vehicle, prompting him to pull to the shoulder of the roadway. After a visual inspection, the contact observed that both trailing arms had become detached. No warning lights were illuminated. The vehicle was taken to an independent mechanic, who determined that extensive frame corrosion had caused both trailing arms to detach. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 143,000.
NHTSA complaint #11587466 — an unverified report by a vehicle owner.
SUSPENSION
While I was driving my 2012 MB C300 4Matic Sport Sedan in Nov', 2023 with history of regular maintenance, noticed a pretty load knocking noise, shudder and drifting to left a bit when it brakes from the driver's rear side especially on the highways. I took it to our local mechanic who was horrified to report that the sub frame was broken and completely rotten out too specifically rust issue with the rear suspension-rear subframe. He gets other German Cars like BMW & Audi even older and more miles in Chicago but none have rusted so much as these MB C-Class cars. Knowing the Dealers wont accept it a manufacturing defect, he was planning to repair it (no chance of wielding that thin metal sheet as the likelihood of breaking it is high). I was surprised to see 2010 Chevy Impala having a much more robust under the cover protection and no rusting with 115k miles. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
NHTSA complaint #11573402 — an unverified report by a vehicle owner.
SUSPENSION
vehicle sub-frame is cracked rusted corroded.
NHTSA complaint #11572697 — an unverified report by a vehicle owner.
SUSPENSION
the rear subframe broke while in motion and caused the car to drift and bounce while i was cornering the traction control and stability control intervened and i also counter steered once back in straight line i braked and the car tilted on the side, we lifted the car in a mechanic shop and found a rotten subframe one side broke the other was almost giving up.
NHTSA complaint #11569388 — an unverified report by a vehicle owner.
SUSPENSION
a rusted rear subframe is more prone to crack when a driver hits a pothole or wants to brake quickly, which can lead to instability in the vehicle's rear suspension.
NHTSA complaint #11554689 — an unverified report by a vehicle owner.
SUSPENSION
My rear subframe has corroded and has snapped, which is a major safety issue as while driving when I come to a stop the rear end of the car swags sideways. It do not stop straight.
NHTSA complaint #11551154 — an unverified report by a vehicle owner.
SUSPENSION
Rear driver side wheel was making a clicking noise leading us to believe there was an issue with the strut and/or shock. Due to the nature and severity of the noise, we took the vehicle to our mechanic ASAP. Upon inspection, mechanic identified that the sub-frame had completely rusted through which could lead to other catastrophic issues making vehicle no longer safe to drive unless repaired. Due to the age of the vehicle being 11 years old, the cost to repair was almost the value of the vehicle basically making this a complete loss. I understand that Mercedes Benz has extended the warranty to 20 years for this issue for other models identifying that it is a design/parts defect but not the C300 although I have found that this is also an issue for this model.
NHTSA complaint #11546160 — an unverified report by a vehicle owner.
SUSPENSION
Failure of rear subframe causes car to lose control. Only found out about the problem after I received a Mercedes extended Warranty in mail March 2023, roughly 6 months after OEM Undercarriage failed and forced me to purchase another Undercarriage in cash/no insurance involved because part back ordered for many months. Car thus inoperable for roughly 4 months. At moment of the OEM failure, total loss of control. Mercedes refuses to reimburse for cost of replacing undercarriage regardless of the fact that failure occurred before notification and regardless of fact that part unavailable for months
NHTSA complaint #11525268 — an unverified report by a vehicle owner.
SUSPENSION
I found out about the Mercedes Subframe failure issue after having problems on the road, that could have killed me, and being warned not to drive anymore by an authorized repair shop because my vehicle was not safe for me to drive. This has caused many other issues with my cars mechanics due to this defect from the Mercedes factory.
NHTSA complaint #11522182 — an unverified report by a vehicle owner.
SUSPENSION
The rear subframe rusted prematurely and broke off important mounts for the suspension and steering. I was driving and had to hard brake. This cause the back end of the car to swerve and almost lose control. I then heard a knocking sound when I pressed the brakes, prompting me to take it into the shop. There I was informed the the subframe was rusted and the vehicle wasn’t safe to drive. I filed a claim with my insurance, but they said it’s wear and tear.
NHTSA complaint #11517601 — an unverified report by a vehicle owner.
SUSPENSION
I was driving on the freeway and had to hard brake due to unexpected stopped traffic. When I braked the vehicle veered hard to the left and almost lost complete control of the car and nearly caused a serious accident. I drove immediately to a local MB dealer and they confirmed what I was afraid and suspected which was the right rear subframe needs replaced. This car was recently sold to me by a dealer less than a month ago and not a single warning light or indicator warning me of this issue. The repair is over 7500 and the shop highly recommended I no longer drive until it’s replaced. This problem is very common and MB actually covers the cost in Europe and Canada.
NHTSA complaint #11515333 — an unverified report by a vehicle owner.
SUSPENSION
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 complaint #11513818 — an unverified report by a vehicle owner.
SUSPENSION
A problem with the rear subframe had occurred in which it had started to rust. Due to the severity of the issue I noticed my car started veering when hitting the brakes as well multiple concerning sounds and stability issues with the vehicle. Mercedes has not contacted me about replacing the part nor has their been any warning lights or any indication of the issue being present other than when the subframe had already been rotted. When speaking to MB about the issue their was nothing they could do for me which is questionable being that the cause of this is a manufacturing issue. I have yet to receive any information as to how the issue may be resolved. Not only does this put myself at my family at risk but as well as the community around me. Wether when braking my vehicle may veer and cause a collision or an issue where the subframe fails and causes an accident.
NHTSA complaint #11511486 — an unverified report by a vehicle owner.
SUSPENSION
The subframe assembly on my car is defective, as I learned today from my mechanic. This issue is known for my model of car and widely reported online. The mechanic says they have seen this issue before. I heard a strange noise while driving so I took the car to the shop after 60 days of enduring the sound. The shop immediately deemed the car unfit for driving and unsafe. In their words, if I had hit one bad pothole, the wheels could have come off the back of my car, and my gas tank could have been punctured, leading to a potentially catastrophic accident. I am lucky to have gotten this defective part identified before being injured, and others need to be protected from this outcome before a serious injury occurs. As of now this has only been inspected by the shop doing the fix. People online have indicated that Mercedes will not fix the problem free of charge - and in fact they charge a premium to other places to replace this faulty subframe. There were zero warning indicators of this dangerous issue - the car drove completely normally aside from an infrequent knocking sound that would occur every 5-10 minutes under normal city driving conditions.
NHTSA complaint #11509955 — an unverified report by a vehicle owner.
SUSPENSION
My vehicle had started swerving when I had hit the brake. I noticed that my rear subframe had been rotting and did more research only to find that this was a common problem amongst Mercedes Benz owners. This is a huge safety issue as not only does it put my cars entire suspension at risk and cause a life threatening accident to me or others on the road it is also very concerning when my vehicle creaks and makes constant noises when driving. There are times it feels as if my vehicle’s suspension will fall out from under it and has been a clear issue Mercedes is aware of yet I have not received any recall notice nor have I gotten any answer as to how Mercedes can help me fix an issue they continuously overlook and sweep under the rug. I fear that eventually something will happen and have been trying to get an answer as to how to get my vehicle repaired without it coming back on me since the root of the issue lies in MBUSA parts snd not on my own doing.
NHTSA complaint #11509704 — an unverified report by a vehicle owner.
SUSPENSION
The left side of rear subframe has rusted out. The right side had been repaired by welding by a previous owner. The damage is still present and can be inspected. The broken bracket is right next to the gas tank and can possibly contact or dent the tank during a hard break or collision. This is a common problem with many people expressing this online and at the 3rd party repair shops. No warning signs were present until the bracket snapped. Extensive rust and corrosion around the area, specifically on the inside of the subframe.
NHTSA complaint #11504516 — an unverified report by a vehicle owner.
SUSPENSION
Issue with my rear sub frame rotting out due to rust almost causing a very bad accident in a hard braking situation
NHTSA complaint #11503802 — an unverified report by a vehicle owner.
SUSPENSION
Cradle and subframe are completely rusted out. This a widely common issue with these cars and am reading it across several forums. Other c300 owners say they have had the exact same issue and request for the MB dealership to fix it. Instead they are given a quote of nearly $10,000 to fix it. MB is responsible for this.
NHTSA complaint #11502013 — an unverified report by a vehicle owner.
SUSPENSION
During planned car service my mechanics discovered that rear subframe is broken and is not safe to drive anymore. After investigation I found that this is a major issue that Mercedes owners have with this particular model. In Europe for this issue has been issued Recall, however in US for some reason Mercedes don't take responsibility. This is a major Safety hazard with possible fatal consequences.
NHTSA complaint #11500152 — an unverified report by a vehicle owner.
SUSPENSION
Sub Frame broke from rust. Mercedes Benz has acknowledged the issue in Europe and repaired/replaced the part at no charge. Numerous problems and complaints can be found on line indicating that we, the car owner must and can complain to Mercedes for partial or complete support on the repair. But they do not acknowledge the problem in the US.
NHTSA complaint #11499206 — an unverified report by a vehicle owner.
SUSPENSION
I was driving our Mercedes Benz C300 and noticed the braking distance taking longer than normal. Also, the rear end responding differently than normal. We took our Mercedes C300 to Mercedes Benz Dealer to be serviced. The technician looked under the car and found the rear subframe rotted out. The service advisor informed us of this being a known defect. We have to be cautious about driving the car until it's repaired due to the fact of being a serious safety issue. MB needs to recall these vehicles and repair them before someone is seriously injured in an accident. Many drivers are uware their subframe has rotted out. I've taken this car to the same MB shop for 8 years and all in a sudden this comes out of nowhere.
NHTSA complaint #11497482 — an unverified report by a vehicle owner.