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
Our vehicle caught fire. My wife and I had just gotten off of the interstate when we started to smell an odd smell. We pulled into a hotel parking lot where we started to see smoke coming from the front of the vehicle. I stopped the vehicle in a hotel driveway, put the vehicle in park. We got out of the vehicle and saw flames underneath the vehicle. We called 911 and hotel staff tried to extinguish the fire but it continued to grow. The fire dept. Arrived and put out the fire. Photos are attached.
Tl* the contact owns a 2009 Mercedes Benz ML320. While driving approximately 60 MPH, the vehicle stalled without warning. The vehicle restarted after several attempts. The vehicle was taken to an independent mechanic who stated that the camshaft position sensor failed and needed to be replaced. The vehicle was repaired. The manufacturer was made aware of the failure. The approximate failure mileage was 60,000. Updated 4/30/15 the consumer also stated the glow plug control unit, heat element and door lock failed. Updated 05/07/15
A seal for the engine oil cooler failed. The cooler leaked oil onto the under-engine pan and was not detected as a leak on the garage floor. Had the cooler failed completely it would have created a safety issue in traffic. The seal failure appears to be a common problem but should not occur under normal use, which is how this vehicle is used.
Both rear brake light assemblies have failed. These failures increase the likelihood of a rear end collision. When the left assembly failed in 2011, I attributed it to bad luck. When the right assembly failed at 66000 miles in 2012, it occurred to me that Mercedes May have a problem that deserves a recall action. Instead of costing about $5 to $10 for light bulbs these assemblies cost about $300 each to replace and install. $600 is enough to cause some people to not repair them and thus create a safety hazard. At 65000 miles I also encountered some very expensive to repair oil leaks that make messes on my driveway and cause water pollution when the oil runs off. Have you had any reports of rear seal leaks, oil pan leaks or oil cooler leaks on this vehicle?
Tl* the contact owns a 2007 Mercedes-Benz ML320. While the contact was merging into highway traffic, white and gray was seen under the hood of the vehicle. The contact pulled the vehicle over to the side of the road and turned off the engine. Prior to the failure, the vehicle hesitated while driving. The contact pointed out that the vehicle was equipped with a diesel engine. The vehicle was towed to the dealer (Mercedes-Benz of annapolis, 324 6th st. Annapolis, md 21403, [phone]) where it was diagnosed with catastrophic engine failure. The exhaust manifold ruptured, which caused the engine wiring harness to melt. The dealer informed the contact that 'the vehicle was done'. The contact's insurance company was notified and the vehicle was awaiting inspection to determine if the vehicle was a total loss. The manufacturer was not made aware of the failure. …
I purchased a used 2007 Mercedes ML320 cdi on March 12. After a week of driving - I inspected the engine compartment (I usually do). I noticed engine oil dripping (small but noticeable amount) on the serpentine belt. I did not think it was urgent - so I took pictures so I can send it to my seller to claim warranty. On March 23, I was driving with my family on I-65. Suddenly, steering became very hard. It was a curving highway so I was forced to go into other lanes. Lucky, traffic was not heavy so I did not swerve into any other vehicle. I was able to wrestle with the steering wheel on time to move away safely. Also, at the same time we lost steering, the battery light went on. After stopping, we popped the hood and immediately noticed the same belt mentioned earlier had disintegrated into several pieces. We called for a tow vehicle. …
Tl* the contact owns a 2002 Mercedes-Benz ML320. The contact stated that the vehicle was riding extremely rough and failed to accelerate. The vehicle was diagnosed by two independent mechanics who stated that the catalytic converter needed to be replaced. In addition, the vehicle was taken to a dealer who stated that the part was no longer in production and that the contact May replace the part with an aftermarket catalytic converter; however, the vehicle May not pass an emissions inspection. The catalytic converter failed on the front passenger side and the contact was uncertain of who would be able to replace the part with an OEM catalytic converter. The manufacturer was notified of the failure. The contact was waiting for them to determine a solution to repair the vehicle. The approximate failure mileage was 150,000.
I was pulling away from the curb, steering wheel started making whining noises and harder to turn. I continued on city streets then to a freeway where my car began to overheat. I pulled over at a gas station opened the hood and could see fluid all over right lower driver side. It seemed to be coming from a hose by the power steering cap and the right side of the radiator. Under the car same spot right passenger side I could see power steering and radiator coolant leaking from that area.
NHTSA investigations
Engine crankshaft pulley failure
The office of defects investigation (odi) opened this preliminary evaluation to investigate allegations of engine crankshaft pulley harmonic balancer failure that could result in loss of power-steering assist.odi has received a total of 546 non-duplicative reports that allege engine crankshaft pulley harmonic balancer failure on all Mercedes-Benz vehicles using the subject component.the subject component failures…
Frequently asked questions
Which Mercedes-Benz ML320 years have engine problems?
By NHTSA complaints, the 1999 (35), 1998 (32), 2000 (29), 2009 (9) and 2002 (8) model years. Engine complaints make up 28% of all complaints for the 1999.
Is there a recall for Mercedes-Benz ML320 engine problems?
No. NHTSA lists no engine & cooling recall for any Mercedes-Benz ML320 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 ML320 engine problems start?
Across all years, half of the complaints with a recorded mileage happened before about 70,000 miles; 21% happened before 50,000 miles.
What part fails most often?
Owners most often name the engine (24 mentions), followed by the engine › gasoline › belts and associated pulleys (20).
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.