2010 MERCEDES-BENZ C300 Complaints

The Rear Subframe of the car rotted out, making the car dangerous to drive. This problem has been identified by Mercedes and IS considered a safety hazard in Canada and Europe. This problem should also be covered here in the USA. Unfortunately Mercedes Benz USA will not offer any help here, instead trying to charge customers more than $7,000.00 for the repair. A frame should last the lifetime of a car, especially when the rest of the car has no to little rust on it. The Subframe is available for inspection, broken suspension puts everyone in and around the car at risk while it is on the road. This issue was inspected and confirmed by a local Mercedes dealer and a local mechanic. There were absolutely no warnings of the issue before it happened.

During service B maintenance, a technician found rear subframe rusted through. Reportedly, there has been a large number of Mercedes C300’s with this very same problem, and Mercedes has a widely acknowledged the issue with rotted sub-frames. It’s a serious safety issue which led to recalls in other countries.

The rear subframe of this vehicle is made of faulty materials and has completely rusted out leaving the suspension components which connect to it in danger of failing. The left rear wheel connecting trailing arm has already detached from the subframe. There have been numerous complaints about the 2010-2013 Mercedes C300 W204 rear subframe, many of which share exactly the same failure as my own. It is a known problem with this generation of Mercedes.

I purchased the vehicle in 2010 & immediately had to have the electrical system for all lights replaced. The lights on the vehicle goes out every 2 mos as if theres an electrical issue. Air bags had a recall & have been replaced now the system states there is a malfunction. This started 09/08/22.

The contact owns a 2010 Mercedes-Benz C300. The contact stated that their wife was driving approximately 60 mph when there was a strange noise coming from the vehicle as well as a shaking sensation. The driver pulled over to the side of the road where the vehicle was towed to their place of work. The vehicle was inspected by the tow truck mechanic who stated that the rear-sub frame had severe rust and was the cause of the failure. The contact had not been taken to the dealer. The vehicle had not been diagnosed or repaired. The manufacturer was made aware of the failure. The approximate failure mileage was 90,000.

Rear sub frame is corroded as shown to me by the Mercedes mechanic in a video he sent me.The car is available for inspection. I am nervous to drive now after hearing about the related problems others are having such as braking issues and swaying when the brakes are applied. The way I found out about the rear sub frame corrosion was when I needed work done at the dealer. This problem should not be happening to all of these vehicles. In other countries, Germany and Canada, to name a couple, Mercedes dealers are fixing this through a recall. Why not the US? The date below is when the mechanic told me about the problem and that it would cost $8000. to $10,000 to repair

Rear subframe completely rusted through resulting in multiple attached systems to break off. When applying the brakes the rear end of the vehicle swings and can force the car into random directions. Upon any basic research this issue can be seen in similar Mercedes models across the globe consistently. If the issue was not diagnosed sooner the likelihood of a fatal crash would have been extremely high due to critical components like braking and suspension systems being nonfunctional. Many vehicles that experience this design flaw are well maintained and kept in good conditions. I urge the NHTSA to release some kind of warning to owners of these vehicles because this issue can blindside even the most vigilant owners. Many posts regarding this issue describe nearly avoiding severe accidents. Please do not let this go unheard because it can be fatal if not addressed.

I need to have my rear brake lines replaced they are blown out but they need to remove the subframe in order to complete the job. They discovered that the subframe is completely rotted and has a hole in it and they believe if they remove it the subframe will break and need to be replaced. They indicated this was a big safety issue and is a known issue on the Mercedes. I was lucky I did not kill myself driving this vehicle. It did come up with warning lamps for the brakes and I contacted the dealership and had it towed there, that's when they discovered the rotted subframe.

Cracks have formed in the plastic cover over the fuel pump in the fuel tank under the back seat. Gas is seeping out when the tank is full.

The dealer noticed that the rear suspension subframe had rusted and corroded with a hole. They rejected the passage of the state safety check. A review of online forums shows this is a common problem in these years and Canadian and German counterparts of MBUSA have issued recalls because a third party supplier provided the parts without sufficient corrosion protection. See eg. https://mbworld.org/forums/c-class-w204/805501-rotted-rear-subframe.html