The car started having a coolant problem at 40,000 miles. The Mercedes-Benz dealership I lived near did not immediately fix the problem, saying it was normal for their cars to run at very high temperatures. A few days after going to their service center, steam started coming out from under the hood. I took it back to them, and they replaced the radiator.
At 42,000 miles, a beeping sound would go off in the cabin whenever the roof separator canvas in the trunk was displaced. Simply hitting a bump would cause this. The dealership was never able to fix the problem. However, pushing the retractable roof button slightly would stop the beeping sound.
At 45,000 miles the passenger side door would not close properly. One would have to slam it to get it to close. I never got this problem fixed.
At 47,000 miles, the retractable roof would not go down when prompted to do so. I brought it to the Mercedes-Benz dealership, but it started to work again before they even took a look at it. When I got home, it stopped working. This was quite frustrating, so I asked them to replaced the wiring that controls the rectractable top.
The driver side brake light started having problems at 50,000 miles. Initially, the bulb was replaced, but the problem persisted. A week after the bulb was replaced, some electrical wires needed to be replaced.
The starter was replaced at 52,000 miles.
The driver side headlight bulb was replaced at 58,000.
The spark plugs were replaced at 63,000 miles.
The interior cabin light was replaced at 70,000 miles.
This car gave me a bit of headache in terms of its reliability. It seemed like I was always making trips to the Mercedes-Benz dealership for maintenance.
On the upside, the car was a joy to drive. It isn't anywhere near as fun to drive as a BMW Z, Honda S2000, or Porsche Boxster, but the hard top is very desirable. The ride could be a little better, especially since its tires are smaller than its other roadster counter-parts. Also, the car has a very heavy feel and does not feel sporty at all. The SLK is entirely too heavy for its own good. Acceleration could be improved as well.
The cabin is roomier than I expected, but the seats are extremely uncomfortable. I'm a young man, and so I didn't think my back could really get sore from riding in a car. Boy, was I wrong. My back would literally ache after driving the car for only 45 minutes. The seats simply are not supportive and cause your back to be in an unnatural position.
I honestly don't think I'll ever buy an SLK230 again. There really are better options out there.