I’ve been enjoying my 1979 Mercedes-Benz 450SL for a few months now, putting about 2,000 miles on it. It still runs with considerable power, though I’ve never driven another one to compare its performance. However, I’ve encountered a couple of issues that need attention. While the car accelerates and brakes well once warmed up, a Mercedes mechanic noted it isn’t running as smoothly as it should. Being someone who prefers to work on my own cars, I’m looking to address these problems myself before considering selling it.
One of the first things I noticed was the condition of the spark plug wires. They were old, worn out, and cracked, with visible sparks around the spark plugs at night. I replaced them with new NGK spark plug wires, hoping it would solve the issue. While the engine runs slightly smoother now, I still observe sparks around some spark plugs, specifically between the spark plug wires/spark plugs and the engine itself. What could be causing these persistent sparks even after replacing the wires?
Another concerning problem is a rough grinding noise that appears intermittently during driving. This noise is most noticeable in the lower gears and disappears when I shift to a higher gear. It’s an automatic transmission, and the noise usually stops after accelerating and then releasing the gas pedal to allow the gear change. If I don’t shift up, the grinding continues, slowing down when coasting and speeding up with acceleration. It sounds like a rusty metal fan grinding against something with each rotation. Has anyone experienced a similar grinding noise in their classic Mercedes? What might be the source of this issue?
I’m located in Berkeley, CA, and I’m open to local assistance if anyone has expertise with these classic Mercedes issues. I’m willing to drive within an hour’s radius of Berkeley to meet someone who might be able to help diagnose these problems in person. Any advice or insights would be greatly appreciated as I aim to get my 450SL running perfectly.
