Which parts fail
Components named in complaints (engine, cooling system, oil leaks, timing chain, exhaust).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2006 Mercedes-Benz R350 owners, lightly cleaned up (personal details are redacted by NHTSA).
My car has stalled several times, either when I am driving, or when I stop at a traffic light. Rough idling and/or running when stopped at a red light or driving at speeds that wouldn't normally be an issue. Engine stalling or misfiring, and car sometimes have trouble starting up. Loud rattling or vibrating noises from the engine. The check engine light is turned on. I took it to Mercedes Benz Dealership in Brooklyn, NY and was told it is a Balance Shaft problem, and they told me it could cost me about $9,000.00. Further research informs me that the problem should not be ignored, nor repair put off. Also, that failure of the balance shaft leaves the inner components of the engine unsecured and therefore will ultimately result in damage to the engine if left unchecked. …
Wiring from engine harness to fuel pump burnt on freeway , engine stalled and shut down, could not start back up in middle of i5 freeway. Repairs are amounting to $4000. Could have burnt entire vehicle and after reading numerous complaints with exact same problem something needs to be done.
Balance shaft gear defective apparently Mercedes has been aware of this problem, class action suits have been filed- no recall yet. I plan to call Mercedes dealer tomorrow- do not anticipate any help on their part - if that's the case will try to join class action suit as this is a known and very costly -(thousands of dollars) problem for numerous mb vehicles- many classes from 2007 -2011. Mercedes Benz was apparently aware of this defect when I purchased my vehicle (used) from local mb dealer here in ny 2009 as a pre owned certified vehicle, why was I not made aware of this issue that Mercedes knowingly knew and come to find out a class action lawsuit was filed. The NHTSA need s to look into this many complaints have been filed, Mercedes service techs were made aware of this issue but they were not instructed to let customers be known of this when cars were brought in for service. …
This is a well documented issue but Mercedes Benz refuses to acknowledge the balance shaft as a defect and road safety hazard. Unfortunately it's going to take someone's engine falling a part at high speed causing an accident before someone will do something which is terrible. Mercedes-Benz balance shaft problems and how to check your car. Balance shaft Mercedes v6 and v8 problems Mercedes-Benz v6 and v8 engines had timing chain problems caused by balance shaft and idler gear failures. Mercedes produced certain models with defective gears in their balance shafts (m272 engines) or with defective idle gears ( m273 engines). These faulty gears wear out prematurely, excessively, and without warning, causing the vehicle to malfunction, the 'check engine light' to remain illuminated, and the vehicle to misfire or stop driving.
My engine light came on - took the car for repair and was told p codes 0016 and 0017 were coming on meaning there was a defective gear in the balance shaft which mb knows about and refuses to take responsibility for. It would cost $6000 to fix. I began to look on the internet to see if any recalls or issues like mine have occurred with others and I found I was not alone and a class action lawsuit had been filed. I want to file a formal complaint as mb should be help accountable for knowingly providing faulty products to customers - they need to be liable to recall and fix every engine affected by this!! The us government needs to protect consumers better than this!
Tl* the contact owns a 2006 Mercedes Benz R350. The contact stated that while reversing, the vehicle made an abnormal noise as the steering wheel seized and smoke started to emit from under the hood. The contact turned the engine off but the vehicle failed to restart. The vehicle was towed to an independent mechanic. The technician diagnosed that the power steering pump, serpentine belt and idler pulley needed to be replaced. The vehicle was repaired. However, the contact stated that the check engine light stayed on. The manufacturer was made aware of the failure. The approximate failure mileage was 130,000.
While I was driving, I lost power steering. I had to pull over and saw that my engine belt was off my engine and a pulley came off my engine. This is after the dealership had already replaced my belt just less than 10,000 before. It was a good thing that no one was hurt. It seems like this engine is defective and Mercedes Benz refuses to fix the problem. I'm afraid that someone who does not know how to handle the loss of power steering will be in a fatal accident.
Vehicle cranks but will not start, dealer first replaced fuel pump ($1500),then when came to pickup vehicle would not start at dealer, replaced starter(no charge), drove for 2 weeks issue came back, took to dealer , they kept it for 20 days and said some sort of control module, but who knows. Its been 15 months and car just stopped smack in middle of freeway at 60 miles per hour and would not start. Currently at dealer.
Takata recall. I purchased my 2006 Mercedes R350 in 2016 with over 100K miles on it. With the engine light already on. I used a scanner tool for an accurate diagnosis. As it stated two issues. A crank shaft sensor/ cam shaft sensor was needed. So I decided against my better judgement to finalize the purchase anyway. Needless to say, after I changed the sensors the problem still remains. After doing a lot of research and spent unnecessary money, it was brought to my attention that the problem is in fact a faulty balance shaft inside of the engine. Due to a manufacturing default. That was covered my Mercedes in a recall at one point before I had purchased the vehicle. …
The contact owns a 2006 Mercedes Benz R350. Regular service and maintenaince has been performed by the dealer only. The contact stated that while driving at highway speeds, the check engine warning lamp illuminates. The vehicle was taken to the dealer. The technician diagnosed that the balance shaft was defective and needed to be replaced. Dtb-s-b-03.30/08i was sent to dealers for this known defective part and corrective measures. The manufacturer was made aware of the failure and offered to cover half of the 7K repair. The vehicle was not repaired. The fiirst time lamp lit was at 72,245 miles but went off. Lamp continued to light intermitted but stays on now more than off diagnosis mileage was 73,845. The current mileage is 75,679.
Engine complaints in other R350 years
Frequently asked questions
How common are engine problems on the 2006 Mercedes-Benz R350?
NHTSA has 33 complaints about the engine & cooling of the 2006 Mercedes-Benz R350, 33% of the model year's 99 complaints. The component named most often is engine (5 mentions).
Is there a recall for 2006 Mercedes-Benz R350 engine problems?
No. NHTSA lists no engine & cooling recall for the 2006 Mercedes-Benz R350, though it has 2 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2006 Mercedes-Benz R350 engine problems start?
Half of the complaints with a recorded mileage happened before about 80,000 miles.
Is it dangerous?
Owners linked 0 crashes, 1 fire and 0 injuries to engine & cooling problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.