The harmonic balancer ground a hole in the upper oil pan and damaged the idler pulley and fan belt. Had it all replaced for a large sum of $, only to get a recall notice shortly after. We did end up getting reimbursement from Mercedes, but only after jumping through several hoops. With the amount of $ they charge for their vehicles, you would think their customer service would be much better to support THEIR mechanical failures (which are incredibly numerous).
2nd recall on catalytic converter. Amazingly the MB dealer found our was "OK" and didn't replace it.
3rd recall for defective lower power steering clamp. Had it fixed, only to have a SECOND recall for the same part as the original "fix" wasn't adequate. Yeah, no kidding as I ended up replacing my power steering pump less than 2 years after the MB dealer supposedly "fixed" the hose problem. Maybe I should ask for reimbursement on that repair as well?
I'm still trying to get a MB dealer to return my call for a 2nd recall "fix" appointment. TERRIBLE service and incredibly overpriced service from all Mercedes "authorized" dealer service centers.
Various poor quality parts, design or defective fittings such as: the interior door panels became dislodged from housing, broken seat latch (rear folding seat), broken driver's side headlamp cover (which of course cannot be replaced without replacing the entire headlamp housing) & broken rear stop light cover.
Cup holders both broke in the front, aside from them being absolutely useless at a depth of about 1.5" to begin with - horrible design.
Power window panel/switches replaced twice already.
Horn (both low & high) replaced twice.
All brakes and rotors had to be replaced, as were the ball joints and rear struts (despite never off-roading or towing or any other heavy stress to the vehicle)
Tensioner, pulley and serpentine belt replaced a SECOND time.
Major (and regular) electrical malfunctions: sensors, lamps, inoperable dashboard displays, et al.
About the only good thing I can say about the ML320 is that it is a very solid vehicle - no worries about the family getting injured in a minor accident - and it handles fairly well, but rides like a truck, not a luxury vehicle. Very hard ride.
I have noticed the ML supporters love to insult those of us who are MB critics by insinuating that we don't maintain or take care of our vehicles. Fact of the matter is, Mercedes is ALL about a name and nothing about quality. Most of the items in the reviews I read have little or nothing to do with regular maintenance, unless of course you're a lifelong Mercedes driver who considers engine and suspension repairs and recalls as "maintenance".
I've driven Toyota's for most of my life, and despite being 1/4 the price of a Mercedes, the quality is FAR superior. Thankfully I didn't buy my overpriced Benz new, so someone else absorbed the incredible decline in resale value for the first couple of years (which is another issue with them - they hold no value whatsoever over the years, despite their 'name').
This is by far the WORST vehicle I have ever owned, and I would never buy another Mercedes. I have told everyone I know the same. Unless you're willing to throw money out the window so that you can boost your ego and say you have a "Mercedes", look elsewhere for something that won't give you the headaches and drain your bank account.