Engine complaints by model year
Which parts fail
Components named in complaints (engine, cooling system, oil leaks, timing chain, exhaust).
Mileage when the problem started
What owners report
Tl* the contact owns a 2008 Mercedes-Benz R350. While driving approximately 45 MPH, the engine made a loud noise and the vehicle shut off. The vehicle was towed to an independent mechanic who diagnosed that the engine needed to be replaced due to a faulty balance shaft. The engine was replaced, but the failure recurred within a couple of weeks. The vehicle was towed to another Mercedes-Benz mechanic where the engine was replaced again, but the failure recurred after a couple of days. The vehicle was taken back to an independent mechanic and the engine was replaced a third time. The failure recurred. The manufacturer was made aware of the failures and provided a case number. The dealer was not contacted. The vehicle was not repaired. The failure mileage was 158,000.
1. Air suspension bag rt side needed replaced. Car was setting low and leaning to right rear- while this was in for repair had mechanic check recent "check engine " light code came up with very serious and expensive issue: 2.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 central pa on dec. 3, 2012.
Replace engine, transmission, 3 suspensions is 3 years-twice on the right side Mercedes and intercar claimed that right rear air spring had a leak left rear shock leaking and claimed normal wear and tear at 71725 miles-so was the pages and pages of the link below at 71000 miles, power door locks stopped working, power drivers mirror stopped working, safety lock for back windows stop working, burns 2 quarts of oil a month, sunroof leaks, and doesn't always close all the way, ABS speed sensors defective, rear main radial seal in transmission defective, replace defective engine thermostat, replaced the batteries due to corrosion (under the seat), faulty signals for tail lights and parking tail lamps (electrical), air conditioning ambient sensor defective, replace defective radio antenna. This car has major design flaws, and has been discontinued by mb. …
Mercedes R350 4matic year 2007, current 80000 miles. 1/ first issue around 20000 miles, ac is not working when used for long hours of driving. Need to stop the vehicle and turn off eng and restart eng then turn ac back on to make it work again. Happend till now 80000 miles. Noise come from all 4 doors due to the gap seal of the all door vibration while driving. 2/ around 40000 miles, power sw window on driver side come off at all 4 buttons just like a pcs knock off of toy. 3/ auto power trunk is not working, belt tenssion pulley broke at 50000 miles. 4/ front brakepad replace every 30000 miles + front rotor replace at 60000 miles, rearpad at 40000 miles. 5/ 70000 miles rear left air shock leak + 78000 miles rear right air shock leak + power sterring leak due to seal ring broke + 77000 miles oil cam plug broke then oil leaking. …
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.
Frequently asked questions
Which Mercedes-Benz R350 years have engine problems?
By NHTSA complaints, the 2006 (33), 2007 (10) and 2008 (5) model years. Engine complaints make up 33% of all complaints for the 2006.
Is there a recall for Mercedes-Benz R350 engine problems?
No. NHTSA lists no engine & cooling recall for any Mercedes-Benz R350 model year. A widespread problem may still be covered by an extended warranty or a manufacturer service bulletin, so ask a dealer.
At what mileage do Mercedes-Benz R350 engine problems start?
Across all years, half of the complaints with a recorded mileage happened before about 76,000 miles; 16% happened before 50,000 miles.
What part fails most often?
Owners most often name the engine (6 mentions), followed by the exhaust system (1).
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.