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Engine
03/01/2025
I’m reporting a serious safety issue with the balance shaft sprocket in my Mercedes-Benz S550 (M273 engine, 273.968). This is a known defect that causes the sprocket to wear out far too early due to poor material design. When it wears, it throws off the engine timing, leading to check engine lights, rough idling, reduced power, and even stalling. In some cases, the engine can shut down while driving, which is a major safety risk. Thousands of people have experienced this exact problem, and it’s all over Mercedes forums, Reddit, and technical bulletins. Mercedes quietly updated the part in later models, which shows they knew the early ones were defective. Some people got repairs under warranty or “goodwill,” but most of us are stuck with thousands in repair bills for something that clearly shouldn’t have failed. This isn’t just a mechanical issue—it’s a safety concern. Imagine merging onto a highway or turning through an intersection when the engine loses power. That’s a real risk wit...
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Fuel/propulsion System
08/14/2024
About 2 to 3 weeks ago I suddenly started smelling faint gas outside the vehicle on the driver side. Over 2 weeks it got stronger and finally I was able to smell it inside and immediately investigated. I discovered the fuel filter underneath the rear seat behind the driver was leaking and the foam under the seat was soaked in gasoline. I did not find my vehicle to be in recall for this safety issue. However, I did find recall 12V-557 for other models that have similar issues with a defective fuel filter. I believe my vehicle should be covered by this recall. I resolved this issue by visiting the dealership and after being told my vehicle was not under recall, I purchased the fuel filter myself from the parts department and replaced it. Included are 2 pictures. One showing crack in the filter that cause gasoline to spray against a cover and leak into the vehicle. And a second picture taken showing the fuel filter soaked in gasoline prior to its removal.
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Electrical System, engine
03/14/2014
The contact owns a 2008 Mercedes-Benz S550. The contact stated while driving 40-50 MPH, the vehicle was shuddering intermittently. The contact stated that the failure recurred while at a complete stop. The check engine warning light was illuminated. The contact stated that the failure had been recurring intermittently. The vehicle was taken to an independent mechanic, where it was diagnosed that the wiring harness was causing an engine misfire. The mechanic related the failure to an unknown recall. The dealer was notified of the failure. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 40,000.
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Tires
09/28/2023
We were traveling home and our TPMS indicated a tire failure. The PSI starting dropping rapidly. We took the tire off and found that only 4 " of rubber holding the back sidewall together on the tire. I then inspected the other tires on the car (which were purchased and installed at the same time) are showing signs of failure as well. All of the tires are 255-40-r19 We had a family of 4 in the vehicle at the time of the incident.
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Power Train, electrical System
07/14/2023
The contact owns a 2008 Mercedes-Benz S550. The contact stated while driving 35-40 MPH, the message "SAFETY" was temporarily displayed on the instrument panel. Additionally, the contact stated while starting the vehicle on several occasions, the message " SAFETY " was displayed on the infotainment system screen. The check engine warning light was illuminated, and the messages "Active Head Lamp Inoperative" and "Service Required. Do Not Shift Gears" were displayed. The contact also stated that upon shifting into drive (D), the gear shift indicator displayed that the transmission was in park (P). The contact stated that the vehicle failed to shift into the intended gear and had become undrivable. An independent mechanic replaced the battery; however, the failure persisted. The mechanic informed the contact that the computer needed to be reset. The vehicle was not repaired. The used car dealer was notified of the failure. The Mercedes-Benz dealer and manufacturer were not notified of the...