I don't have a clue as to the problems, but I just wanted to say that you likely will be able to force MB to eventually fix this, even after the warranty expires. You have a well-documented history with this problem, and it's not your fault that they've taken so long to not fix it. I'd take it back, tell 'em to fix it, and don't bother me until it's fixed.

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1989 300 SEL that mostly works, but needs TLC