I have a problem starting a 1981 300cd. When you turn the key, I only hear a click sound that seems to be coming from the engine bay, but i haven't been able to pinpoint it exactly. The battery seems to be fine (lights work, etc) and i even tried jump starting it with a truck and it still didn't crank. I was wondering if there is some relay for the starter or if it's most likely the starter that is fautly. I recently had the glow plugs changed since the car didn't start before, but it did crank. The mechanic was cranking the engine for long periods of time to get it started so I'm thinking maybe it just wore out the starter. He also managed to break the key, luckily I had a spare, but now it'shard to turn the key sometimes. I'd appreciate any suggestions, before i go buy a starter. Thanks.