2012 Mercedes-Benz C300 complaints

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.

The contact owns a 2012 Mercedes-Benz C300. The contact stated that while driving approximately 55 MPH and pressing the brake pedal, the entire vehicle shifted to the left. Additionally, while driving at various speeds the vehicle was unstable and experienced vibration. The vehicle was taken to an independent mechanic who discovered that the subframe of the vehicle had severe rusting and corrosion and that the vehicle was unsafe to operate. The vehicle was not yet repaired. The local dealer and manufacturer were not notified of the failure. The failure mileage was 95,000.

My vehicle has 70,000 miles. always kept garaged. Told by dealer when taken for the yearly checkup that the rear subframe of the car is totally rotted. Needs replacement. Price $3790. Mercedes would only cover 20% of the cost. There have been recalls in Canada with the same issues. Please investigate as this is a serious defect problem and not a warranty issue as Mercedes is claiming.

Premature subframe rust, causing the vehicle to swerve when brakes are applied looks to be a trend: https://www.benzworld.org/threads/2012-c300-rear-subframe-any-updates-on-recall.3086018/page-6

The contact owns a 2012 Mercedes-Benz C300. The contact stated while driving at various speeds, the rear end of the vehicle was shaking and vibrating abnormally. While the vehicle was in for routine maintenance, it was discovered that the rear subframe was severely rusted. The cause of the failure was not determined. The vehicle was not yet repaired. The manufacturer was not notified of the failure. The failure mileage was 65,000.

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.

Issue with my rear sub frame rotting out due to rust almost causing a very bad accident in a hard braking situation

The contact owns a 2012 Mercedes-Benz C300. The contact stated that while parked, the vehicle failed to start. The vehicle was towed to the dealer where it was diagnosed as having water intrusion. The vehicle was not repaired. The contact referenced the failure to NHTSA Campaign Number: 22V955000 (Fuel System, Gasoline, Fuel System, Diesel). The manufacturer was made aware of the failure. The failure mileage was approximately 109,000.

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.

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.

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.

The contact owns a 2012 Mercedes-Benz C300. The contact stated while driving 30 MPH, she started hearing an abnormal sound. The contact stated no warning light was illuminated. The contact took the vehicle to the local dealer, where it was diagnosed with needing the rear subframe to be replaced due to severe corrosion. The vehicle was not repaired. The manufacturer had been informed of the failure. The failure mileage was approximately 120,000.

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.

The sub frame broke in half and the dealership said it is due to rust. The car has been garage kept and not driven much at all. It’s a 10 year old car with only about 55,000 miles on it. It’s been used very gently.

The contact owns a 2012 Mercedes Benz C300. The contact stated that while driving 45 MPH, the contact started to lose control of the vehicle while depressing the brake pedal. There was no warning light illuminated. The contact regained control of the vehicle and drove to a dealer. The vehicle was inspected, and the mechanic discovered that the subframe had fractured due to severe corrosion. The contact was notified that the vehicle was unsafe to drive. The contact was provided an estimate for the repair. The manufacturer was also notified of the failure and informed her that 15% of the cost of the repair would be covered. The vehicle was not repaired. The failure mileage was approximately 62,000. The contact stated that their vehicle was finally repaired by the dealer in Dec. 2022. The manufacturer helped pay approximately 13% of the total repair costs.

Rear Sub Frame Assembly failure. It is available for inspection upon request. Vehicle rear end begins to wobble at speeds above 40 mph. The issue causes steering to become more complicated and the vehicle veers sharply while braking. This issue makes all C Class vehicles with this Sub Frame Assembly extremely unsafe, especially at highway speeds. Vehicle has been inspected by the authorized Mercedes Benz dealership in Indianapolis, IN. Service Advisor stated it's "amazing" that there hasn't been a recall issued yet. Based on this body style there have been roughly 320,000 of these C-Class vehicles sold. If the NHTSA truly cares about safety, they will launch an investigation into this matter. There are no warning lamps or messages that appear prior to this failure.

I purchased a 2012 Mercedes C300 AWD from a local dealer and have had it serviced annually. Last week I took it in for the annual servicing and was told by the dealer that the rear subframe had corrosion /rust and the car was not safe to drive. I asked if it was covered under a recall and they said not by Mercedes at this time.They provided a repair estimate that is quite high and close to the appraised value of the car. I asked if there were any options available through Mercedes or the dealer and they confirmed not at this time. I have read many articles related to this problem and imagine there are many complaints on file at NHTSA. This is obviously a serious safety issue and currently Mercedes is not taking responsibility and directing the costs to their customers. In addition there is a subframe parts shortage and it could take weeks to fix. I'm requesting that this be listed as a recall item by Mercedes.

The contact owns a 2012 Mercedes-Benz C300. The contact stated while driving 35 MPH, the contact heard an unusual noise coming from the rear of the vehicle. The vehicle was taken to the dealer, and the mechanic stated that the rear subframe was rusted and the passenger’s side rear control arm was detached from the subframe. The vehicle was repaired. The manufacturer was contacted and stated there was no recall for the failure. No other assistance was offered. The failure mileage was 43,960.

Corroded rear cradle driver side. Causing instability driving. Cradle on back order for months according to local Mercedes parts department

Applied brakes coming down a slight grade and vehicle made a clunking noise and became unstable. Pulled and pitched as brakes were applied and released. Upon checking brakes it was very visible that the rear subframe had failed on the right side and the left was severely compromised. I hard braking situation would have resulted in a crash… The severe damage was not visible a week ago until it rotted out from the inside and failed under load.

As per an inspection by my mechanic, the rear sub frame of the vehicle has cracked due to rust corrosion and subsequent metal failure. I first noticed the issue when there was a thumping sound over bumps and the car started to swerve when applying brakes on the highway, quite a scary situation as I thought the brakes were failing. The car has 78000 miles and has had all maintenance done. The is no other rust on or underneath the car. According to my research on Mercedes-Benz owner forums I discovered that it is a common issue and that, so far, Mercedes Benz has not issued a recall in the US. According to these forums Mercedes has issued recalls in other countries (although I have not confirmed this point). The estimated cost to replace the sub frame is $3000 including labor and there is an 8 to 10 week backlog for the part due to the number of failures occurring. In the meantime I cannot drive the vehicle as my mechanic has told me that the car is not safe to operate.

This issue concerns rear Sub Frame corrosion. My car has always been serviced at the Mercedes Benz dealer where it was purchased as recommended. Upon recievieing my car after a service I was informed that the subframe in my car was badly damaged by metal corrosion. In fact I was told that the car was unsafe and should not be driven as total failure would likely cause lose of control of the vehicle. I was offered a repair quote in excess of $5,000 to replace the rotten subframe. I have since found that this failure is common the the model and many cases have been reported. In Europe and Canada recalls have been issued. Cases in the US are apparently felt with on a "case by case" basis. I see this as a serious safety concern for our highways. Failure is common from reports and and serious accidents surely possible. I have removed my car from service, but many are being driven right now. Mercedes Benz is aware of this and is doing nothing to date to take responsibility for this design/construction defect. I add my voice to the many that I hope have contacted you with concern.

The contact owns a 2012 Mercedes-Benz C300. The contact stated that upon taking his vehicle to a dealer for maintenance repairs; he was provided an estimate for the repair of corrosion to the rear subframe of the vehicle. Upon investigation, the contact discovered that the failure could lead to a potential braking system failure. The manufacturer was notified of the failure and informed him that there were no recalls on the vehicle. The vehicle was not repaired. The failure mileage was approximately 97,000.

I have a 20212 Mercedes C300 with 70,000 miles. I took it into the MB dealership for inspection and was told that the rear subframe was rusted through. The subframe's failure also caused the brake lines to rust to the point of needing to be replaced. The subframe repair will cost $5,900 and the brake line replacement will cost around $1,200. The dealer told me the car couldn't be driven safely, so I had to leave it there to be repaired. There were no interior warning alarms about the structure or the brakes. According to forums on Benzworld.org, this is a known problem on these specific cars and the component is replaced for free by MB in Europe.

The rear subframe rusted and completely cracked. The car started to shake violently while I was on the highway. Fortunately I was in the right hand land and was able to slow down. I was driving in the car with my mother. My understanding from the mechanic is that we were lucky not to be killed or hurt anyone else. The frame is completely cracked. I called the local dealership and they said this is an extremely common problem. So common they have multiple vehicles on the lot waiting for parts, and the waitlist is indefinite. There were absolutely no warnings on the car.

Car is leaking gas very dangers . I contact Mercedes dealer regarding the recall on this type of Mercedes i have and they said only vehicles manufactured from April 18, 2011, through July 12, 2011. Mine was before or after , and they refuse to give me the exactly date for my car manufacturer. Car I use for Uber , and i don’t have any other income . If someone just through away a cigarette in parking lot might cause a big problem in the building and others cars in parking

I went to my dealership for a routine yearly service appointment, which I do regularly, along with yearly inspections. My car was purchased new to my liking in 2012 with input from my late partner who passed before I received it! I waited quite some time to get my gem. When it arrived, I had all I could do to drive it, given my loss. I garage it every day for the last 10+ years, never left it outside, it is pristine, only has 64,000 miles on it. To my disbelief, was informed by the MB technician yesterday that I have corrosion on my left rear sub panel, and that I should not drive it and consider a trade-in - NO WAY!! And that the part would cost me over $4,800 to replace and it would not be available until February 2023. So, I should drive another car, which I do not have!!!!! After researching, I am beyond disappointed that this is a known MB manufacturer's defect that has gone this far, customer action needs to be taken!!! My local car dealership states they knew nothing about this, however; pointed out a number of Mercedes C300 in their parking lot sitting with the same life-threatening issue. They were eager for me to talk to sales for a trade-in. Go figure this strategy, NOT. I have had three Mercedes Benz which I love, I do not want to part with this gem, but my need to . . . Please do something . . . Safety and Life matters

The contact owns a 2012 Mercedes-Benz C300. The contact stated that the vehicle was taken to the dealer for a routine maintenance check and she was informed by the dealer that there was a hole in the subframe. The contact was informed that the subframe needed to be replaced. No warning light was illuminated. The vehicle was not repaired. The manufacture was not notified of the failure. The failure mileage was approximately 80,000.

The contact owns a 2012 Mercedes-Benz C300. The contact stated that upon parking the vehicle at the dealer parking lot, she heard abnormal sounds coming from the rear of the vehicle. There was no warning light illuminated. The dealer diagnosed that the rear subframe was severely corroded and the rear control arm was detaching from the subframe. The dealer diagnosed that the subframe needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline. The failure mileage was approximately 79,000. The contact was informed by the service advisor that the vehicle should not be driven until it is repaired due to the extensive damage to the subframe.

Rear Subframe Cracking in Mercedes Benz 2012, C- Class, Sports. It can be life threatening for driver and passengers. Cost is $5700 for repairs. This replacement is free in Europe and Canada.

My Mercedes 2012 C 300 is leaking gas which may lead to fire ( the fuel filter flange when operated in high temperatures

Rare Subframe breaking off parts are not available for at least 6 months. I have kids and mechanics advise me to keep it off the road. My only means of transportation

The back sub frame rotted away from rust

The contact owns a 2012 Mercedes-Benz C300. The contact stated that while having an oil change performed on the vehicle by an independent mechanic, he was informed that the cross member was severely corroded. The contact was informed by the mechanic that the vehicle was unsafe to drive. Neither the dealer nor the manufacturer had been notified of the failure. The vehicle was not repaired. The failure mileage was approximately 125,000.

The rear subframe rotted away

The contact owns a 2012 Mercedes-Benz C300. The contact stated that the vehicle was taken to be serviced under an unknown recall however, the mechanic informed him that the rear subframe was severely rusted, creating holes in the subframe. The dealer diagnosed that the subframe needed to be replaced. The vehicle had not been repaired due to the part being on backorder. The manufacturer was made aware of the failure and informed the contact that there was no recall or warranty coverage for the failure. The approximate failure mileage was 65,500.

Diagnosed with broken rear sub frame: "Broken rear sub frame, left side lower link is broken off and contacting Fuel Tank. Rear tires are also bald and care is unsafe to drive". Recall in Canada, but not USA. Sub frames on backorder until January 2023. I have three years of payment left, and am now being quoted 6,300 from the MB Service Ctr in Wilmington DE to fix this problem. Again, the items are on backorder due to heavy demand. Im a single mom we depend on my car to get us to work. This is the ultimate catch 22 as the car is extremely dangerous to drive and put us all in serious jeopardy - but no one will take this broken car as a trade in. I am forced to drive the vehicle while I wait for backordered parts and pray that I can get a loan to pay for it. "".....and contacting the fuel tank".....

The W204 subframe of my Mercedes Benz C Class is failing and in need of repair, this should not be happening to a car with less than 80K miles on it. My local auto repair shop which exclusively services Mercedes Benz currently has two vehicles with the same issue and informed me that the subframe part is currently out of stock due to the number of failures. This issue has caused a recall in other countries. What is the NHTSA doing about this issue. I will be contacting my congressional representative today as well.

The contact owns a 2012 Mercedes-Benz C300. The contact stated while driving 25 MPH going downhill, the rear end of the vehicle shifted independently to the right. The contact stated no warning light was illuminated. The contact was able to continue driving at a slow speed to her destination. The contact stated her husband inspected the vehicle and became aware that the rear subframe cross member had fractured due to corrosion. The vehicle was not diagnosed or repaired. A dealer was not contacted. The manufacturer had been informed of the failure. The failure mileage was approximately 149,000.

Subframe corroded/rusted out. Car is in excellent condition with no other rust or corrosion. Car has 58,800 miles and regularly maintained by dealer. Took car to TireDiscounter because of noise. Mechanic put car on lift and reviewed corrosion and other damaged cause by failed part. Mechanic called MB service department and was told that parts on 5- 6 months back order because of this issue. But no recall even though problem is wide spread. Rear tires and gas tanked damaged by loose subframe.

- Right Rear Subframe; Yes, available for inspection. - My mechanic told me that driving the car more than 2 miles or at a high rate of speed was very dangerous. He told me there that if the car braked quickly or was driven at a high rate of speed that there was a very good chance of an accident. There is a risk of the right control arm detaching from the frame; this could cause the car to be uncontrollable with the right rear wheel and control arm detaching from the vehicle. - Yes, the issue was confirmed by my mechanic, who works at an independent service center. - No. - There were no warning lamps or messages. I had begun to hear a loud clunking noise, usually when braking.

I’m filing a complaint due to a concern regarding the rear subframe of my vehicle becoming rotted/rusted out and falling apart at any time. This is due to a Mercedes Benz manufacturing issue where they tried cost cutting which turned out very poor quality materials for this very important assembly. I have researched online about this problem, and turns out, it is very common with this body style c300 ('08 - '14). There are hundreds, if not thousands, of individuals within the USA who are having this exact same issue with as little as 60,000 miles. Most are happening around the 90,000 mile mark however. They primarily mention in many online forums how scared they were when it happened and how lucky they are it didn’t cause a major accident…yet. My car only has ~110,000 miles and is just about 10 years of age. This issue should never happen for a vehicle with such low miles and such a short life, especially from a prominent and distinguished automotive company. This is a Huge Safety Concern, and I am Scared that this subframe will fail without warning and at a high speed, which can likely cause me to be involved in a major accident where people are killed or seriously injured. It is astonishing how this subframe was not recalled by now and how Mercedes USA has not taken responsibility for this. This issue needs to be addressed and recalled Immediately before people are killed or seriously injured, and before more of these parts break. Please look into this very soon as this is

The contact owns a 2012 Mercedes-Benz C300. The contact stated that the vehicle was taken in for a routine service check at the dealer and the mechanic informed her that the rear subframe was rusted and the vehicle was unsafe to drive. The contact was informed that the part was on back order. The manufacturer was not contacted. The failure mileage was 119,000.

I ran off the road and my rear suspension sub frame literally broke in half. Upon further research I’ve learned that these parts are faulty and several people have had theirs rust completely in two. Mine had lots of rust damage and that is likely what caused the damage to mine when I ran off the road (MINOR impact that should have never caused that much damage). Mercedes has recalled this part in several countries including Germany and Canada. When I drove home after running off the road my car was nearly impossible to drive. It was jerking all over the road and when I tapped the brakes the rear end of the car would come up off of the road (into the air)! This was in June. It’s now September and I still have not been able to obtain a part from Mercedes. So many people are having this issue with their vehicles that the part is on back order until Q1 of 2023. This is a part of the cars sub frame that is rusting in two! One would argue a broken sub frame is dangerous. And it’s such a prominent issue the part is on back order. Furthermore, Mercedes has changed the type of metal used in replacement parts, which is an acknowledgment of the parts defect.

The Rear Subrame CRACKED while Driving, Almost causing a Major accident with my son in the car as well. This seems to be a MAJOR problem being overlooked and ignored by Mercedes Benz . This repair is going to Cost me $ 3000-$ 5000 Dollars. and the Replacement Subframe is Impossible to find and on Back order ! so Now I'm without a Vehicle for God knows How long ?? I Feel there is No Doubt this is a Defect and Should be Covered by Mercedes Benz and a Recall ! How is this not being investigated is Really Scary. How can a Frame or a Car just Crack ? That's Not safe for ANYBODY !

During a routine oil change Mercedes mechanic discovered our rear subframe is rusted on both sides and needs to be replaced. This is apparently a well known problem, and Mercedes will replace this for free in Germany, but has not recalled the subframes in the US. Mercedes created a new OEM part as the replacement part, proving the original part is faulty. However Mercedes does not have enough parts ane every mechanic we have spoken with has several subframes on order for months at a time. We have waited 9 weeks at this point. Many Mercedes drivers subframes have broken making the cars undrivable.

Dealer states that the rear subframe has rusted and degraded to the point of requiring full replacement. The car is 10 years old with 98,000 miles on the odometer. This is premature degradation of an essential component.

The contact owns a 2012 Mercedes-Benz C300. The contact stated that the vehicle was unable to start-up as needed. The vehicle was towed to the dealer where it was diagnosed with a faulty steering column sensor that needed to be replaced. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was 104,692.

Took my car in for inspection at the Mercedes dealership. They advised the rear subframe was rotted or rusted. This occurred from the inside. The vehicle is garage kept. They advised Mercedes has no re-call on the issue in the United States. They are covering the issue outside the US. This is a major safety issue.

The contact owns a 2012 Mercedes-Benz C300. The contact stated that the vehicle was taken to the dealer for an airbag inspection. During the inspection, the dealer informed the contact that the rear subframe was corroded. The vehicle was diagnosed and the contact was informed that the brake lines and rear subframe needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 120,000.