Recommend having your 300SEL flatbedded to the MB tech. With the car at his shop he will be able to properly diagnose the problem, and you won't be paying for his roundtrips to get more parts.

Your car looks far too nice to even consider parting it out. I suspect it's a relatively minor problem that an experienced MB-trained tech familiar with your vintage automobile can pinpoint quickly. You want to avoid selling your car in desperation, and have someone else spend $100 to repair the problem.

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Fred Hoelzle