Mercedes ML 320 TDI Issues
 

This past year my son bought an used 2007 Mercedes ML320 TDI with 150K and drove it 20K sinc the date of purchase.
He is a very careful person with his cars but is extremely disappointed with the number of problems that this car is giving to him. According to the seller, a private dealer paperwork, this car was carefully maintained and serviced by MB dealers.
In only one year this car had four major problems taken a good amount of money in repairs performed by a local shop repair. The shop only work with European cars.
Here is the problems that this car already had:
1- Turbo over boost code. Mechanic replaced the turbo which was with a waste gate valve broken. Spent around $ 3K
2- Exhaust Filter clogged. Mechanic try to clean but finally had to replaced the exhaust filter. Spent around $ 1.5K
3- New issue: Air Suspension not working, car have a rough ride. Not yet fixed.
4- New issue: Transmission does not shift from first gear. Need to stop the car and start again. Not yet repaired.
The reason why he bough this Diesel car is because it was more economic going and coming from his work.
He and I will appreciate if someone share with us if there are some bad historic about this car year of manufacturing or any other possible reason for so many issues on this car.
Thanks.

None of those repairs seem unusual considering the 2007 was a first-year model and 150k+ miles is a lot to expect nothing to go wrong.

Transmission issue could be the conductor plate, or a stuck solenoid. Shop will need to pull codes to figure it out most likely.

An early ML (or R) 320 CDI is not likely going be an economical vehicle....

The adage is that if you own an old Mercedes you are rich or a mechanic.
If you can't fix the bulk of the stuff yourself the alternative to taking the time and trouble to fix it yourself is if you have a job that pays really well and can spend time working overtime to build up a fund to fix the Car.

If the "Exhaust Filter" was actually the Trap Oxidizer you might have checked with Mercedes to see if they had to fix it for free as they had to do on the older models.

Remove the DPF and install a test pipe.
Get a tune that eliminates the regeneration cycle and ignores the DPF pressure sensors.

Much cheaper than replacing the DPF.


There are also services that will bake the DPF clean.

Most of the big repair bills in our shop are on the 642 motor. IMO, these are money pits. The turbos, oil cooler seals, particulate filters, injector coking,etc. Back in the day when MBZ made a reliable diesel, they were worth owning. They were low maintenance, reliable, had good fuel economy and diesel fuel was cheap. Non of these reasons apply today except good fuel economy that is absorbed by costs and repairs ten fold. IMO, there's really no advantage to owning these as opposed to their gas counterparts.

Except the gas counterparts of those years have balance shaft issues, so it almost seems like a no win situation

I guess if you buy a new one you need to sell it of just before the warranty expires.
A Prius is likely sounding like a better choice.

The later ones seem to have the kinks worked out much better than the early ones. Also the 4 cylinder OM651 is a beast and seems to be much more reliable. I have one and its been rock solid! I had the dealer pull the history on it when I bought it....no repairs/warranty services needed ever, and its at 73k miles now

And its true that the 350 gas motor of the 2007 era had balance shaft and timing chain sprocket failures leading to engine out major repairs (several grand $$) My dad's E350 wagon had the problem but it was fixed by the dealer....unfortunately its now throwing codes again 25k later for cam positioning....

True. You just need to stay away from the 272s prior to 08. But, they all seem to have their own individual issues. I've owned MBZs since 1982 and have worked on them since 1992. When we're done with the ones that my family and I have now, I'm moving on to a different make.