Number one thing to watch for is rust. Rockers and quarter panels rust out. Check them carefully and I would pass on any car with substantial rust unless it is a throw-away price. These are unibody cars so the rockers are part of the car's "structure".

You can run any biodiesel up to B100 in them though you might have to replace some rubber hoses in the fuel system but it is no big deal to do that. The W115 is an especially easy DIY car, very simple and intuitive in most cases to work on. Good luck with it.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz