Worst reliability of any vehicle I have ever owned
written on 09-14-2015
The engineers who designed the vehicle did a good job. It is spacious, comfortable, quiet, has a fantastic range on long distance drives - up to 700 miles on one tank 95 liters / 26.5 US gallons. I still love driving it after almost 7 years. You can drive 800 miles in one stretch and exit the car still feeling fresh. The strong torque of the Diesel engine with up to more than 30 mpg, the transmission working seamlessly in the background, the comfortable ride, the quietness of the cabin, the excellent seats make this a wonderful vehicle. BUT THE RELIABILITY IS TERRIBLE! This is hands down the worst vehicle I have ever owned in terms of frequency and cost of repair (see below), and these cars include 2 Jeep Cherokees when they were still made by AMC. While my local dealer is very very good, Mercedes Benz of USA and the folks in Stuttgart were of no help whatsoever. Verbatim from a MBofUSA representative: "Sorry, there is nothing we can do for you. We suggest you negotiate a real good deal with your local dealer when you buy your next Mercedes." Repairs & Parts replaced on my 2009 Mercedes ML-320 Bluetec in 6 years & 10 months and 73,696 miles light duty use. 01. Factory recall: Tail lamps, rear lights, power lift gate module replaced 9cost not known) at 5,176 miles 02. Warranty work: Noise from front end; replace right front wheel bearing at 27,670 miles 03. Warranty work: Replace left strut assembly front and replace buttons on steering wheel at 32,477 miles 04. Warranty work: Removed and lubricated shift paddles on steering wheel to fix squeaky noise at 32,620 miles 05. Warranty work: Replaced defective NOX sensor at 35,866 miles 06. Warranty work: Left rear door lock assembly replaced at 42,541 miles 07. Repair NOT covered by warranty: replaced auxilliary heater in AdBlue tank diagnosed at 49,671 although it is part of the emissions control system but NOT covered by MB emissions control warranty (read the small print); paid out of some slush fund after my vociferous complaints to MBofUSA; cost estimate almost $2,200.-; fixed problem at 50,843 miles 08. Repair: Front passenger door lock assembly (same broken part as above, different door) $833.99 after 15% dealer courtesy discount at 53,277 miles; MBofUSA refuses any consideration. 09. Repair: Noise from engine department - loose NOX sensor - tightened - no charge at 56,633 miles 10. Repair: Replace 2nd NOX sensor and EGR temperature sensor and air cleaner turbo seal at 60,028 miles; this NOX sensor lasted 24,162 miles; cost of repair $1,350.92 11. Repair Turbocharger intake shut-off motor, seals, gaskets, pipes (almost left me stranded) at 66,241 miles; cost $1,675.89 12. Repair: Bad Glow Plug Control Module at 68,9921 miles; cost $503.64 13. Repair: Oil leak in front engine area. Turbo Pipe Gree O-Ring Seal and seal on oil breather assembly black o-ring seal; oil squirted on V-belt; replaced free of charge by dealer as it was possibly related to repair #11 not performed 100%; dealer otherwise very good and VERY HONEST. Same mileage as Repair #12 done at same time. 14. Replace 3 engine mounts / support struts. They were leaking fluids; at 73,696 miles; $1,774.38 15. Replace temperature sensor upstream of turbo at 73,696 miles (as in #14); cost 737.98 Estimated cost of warranty repairs $5,000+; repairs paid by owner $6,876.80 (does NOT include windshield replacement caused by stone from passing truck or self inflicted body damage); additional regular maintenance cost incl. tire replacement $8,391.98 (does NOT include registration, SMOG check, insurance, fuel); total estimated cost for all repairs, incl. warranty work, and regular maintenance ~ $20,268.78; Days in service 2491; average number of days between repairs (does not include regular maintenance trips) 166; average number of miles between repairs 4,913. UPDATE 1: The car now has 80,750 miles on it and nothing has broken since my original review. That is about 7,000 miles without something breaking, although I did have a brief scare at about 76,000 miles when the car lost power on a long uphill portion on the freeway and slowed down to about 35 mph. I managed to pull off the road [slow trucks were using the emergency lane], turned off the car, and after about 5 minutes restarted it. It has been running fine ever since. A visit to the dealer did not show any recorded error code. About 30 miles earlier I had added fuel when the tank was still half full. Maybe the fuel was dirty and caused a momentary clogging. I still love the design and how it drives very much, it is just the reliability that I hate. But I may have gotten a particularly bad one-off example. UPDATE 2: At 80,915 m replaced defective 2 front air suspension struts & air compressor & 4 new tires as a result, new turbo inlet pipe seals, new transfer case input shaft seal, incl. C-Service $7,303. 15 unscheduled stops so far not counting light bulbs. Repl. backup camera (warranty), est. $2,400 incl. module.
If you are interested in a beautiful looking SUV that is comfortable and will cost you more money in repairs than you have ever experienced before; then this is the vehicle for you! Here are the items you need to make sure have been replaced before you purchase one/ if they have not been replaced; plan on saving up because those dark day(s) will come. Oil cooler seals: $2500+ NOX sensor replaced if you do it yourself (1) $450 if the dealer does it over $800; note** there are two NOX sensors Shocks and struts: $2300 Air Mass Flow Sensor: $750 Regular 10k maintenance avg: $350 (always ask what is being performed) Fuel Filter: $240 Seat Belt: $750- Manufacturer defect that mercedes will not own up to. Brakes: Mercedes does not believe in rotating rotors; they replace them with the pads. What does this mean; more $$ There are probably more to come; i may find out or i may wave the white flag and try to get rid of it. I will put it to you the best way i can; i have owned a variety of diesels for over a decade including foreign diesel powered vehicles. Pass on this one; this has been a money pit compared to the 10 diesels i have owned. I have only owned this vehicle for 2 years and look how much i have spent; this is a fun vehicle to drive and has every bell and whistle; but you will pay to have the luxurious Mercedes-Benz named vehicle.
We bought this to replace the 1998 ML320 we had for eleven years. The old one was great and gave outstanding reliability, but it was time to replace. This ML320 BlueTec is a great replacement and it has lived up to it's advertising. Great mileage and comfort with all the gadgets you would want. Very solid feel on the road with plenty of room for storage. We have other diesels in the family and this is one of the best. It is quiet and soot free with good mileage for the weight of the vehicle. On the road you don't even know it's a diesel. Fantastic improvement over the older diesels.
This has been a wonderful driving experience .The Diesel is very smooth and quiet and the highway milage is regularly over 28 mpg with average usually around 25 including city. The interior systems are fun and easy. The lift gate is great and at the right height to the ground and the space is more than ample.
I buy a new car about every two years and just traded in a Jeep Commander Limited with a Hemi in for this new oil burning Benz. All I can say is: WOW. This truck is the bomb, I have only driven it about 1,000 miles so far but am averaging 30mpg on the highway and about 22mpg in town. I got nearly every option, including prem packages 1 and 2 (keyless entry) and leather, etc. The ML320 is like an S class in overshoes, the ride is first rate and the gas mileage is simply amazing for such a large vehicle. The only complaint I have is that from 0-10 mph it is a little herky jerky until the turbo kicks in then it flies. The fit and finish is typical MB and is my #1 choice in a luxury SUV.