My long-standing reliable mechanic was a bit out of his depth on this car. I transferred the car to another mechanic and a separate auto-electrician when he couldn't work out why it was throwing codes, and I discovered it was because he left the secondary water pump unplugged. I accidentally found an awesome independent european car workshop when coolant leaked into my oil while I was in another town. The official Mercedes shop refused to touch it, but these guys embraced the car - having worked on them before - which was a relief. I have since learned a lot more about working on the car myself. I'd rather not, but to save money I have to.