Faults:

Engine failure.

Multiple sensors failed.

Seat heating failed.

Door trim got loose.

Alarm constantly drains the battery.

Automatic roof got stuck.

Rust at the rear window.

General Comments:

Let me start by giving a warning. When considering a Mercedes Benz, with a V6 or V8, from between 2004 and 2007, these engines have major problems. Mercedes has used, due to cost savings, inferior steel for the crankshaft cogs. This causes the engines to fail somewhere between 70000 km and 130000 km. If you want to buy any Mercedes with a M272 or M273 engine from these years, make sure the engine has been rebuilt. If not, repairs will be costly.

The above happened to me. The dealer quoted a 6000 euro repair bill (+/- 8000 dollars). Even though Mercedes is responsible for causing these problems (cheap materials), they were not willing to pay the bill.

Besides that, this car has multiple design flaws. Because of the roof design, water tends to accumulate under the rubbers at the rear window. This causes rust at the underside of that window. Very expensive to repair (add another 3000 euros), because the whole window has to be replaced.

This is my second Benz (out of three) that has problems with the door trim coming loose. I've never had these problems with any other brand, only Mercedes. The seat heating has never worked on any of the 3 Benzes I owned; it seems it dies within 4 years after purchased new.

This car has 2 batteries, one for starting the car and one for the accessories and the alarm. This seems like a good idea, because then the alarm cannot drain the battery in such a way that the car cannot be started. However it seems this is done by Mercedes as a fix for a more concerning problem. The power consumption of the car when standing still is way too high. I have replaced the accessory battery twice in 18 months, and still it was almost always drained when the car was not used for about 3-4 days. This also means that you cannot open the roof when starting the car (it is connected to the secondary battery). In practice I had to drive for about 20km before the battery had enough charge to open the roof.

All in all, I was very disappointed in this car. I bought this car because it was always one of my dream cars. But it turned out to be a nightmare. After 18 months I got rid of it and I am now a happy owner of a BMW 335 convertible. Given the way Mercedes has handled the problems with my SL (read: they refused to do anything about the problems they caused themselves) I will not buy a car from Mercedes again.