Interesting discussion.

Oil changes are a MUST, no matter what oil is being used.

On the recommendation of my mechanic, I switched away from synthetics on my 560 SEL with 104k miles on it. He felt that you should change the oil and filter every 3k to 4k, and the cheaper, standard oil is just fine for those inervals.

Why?

Because of sludge. He felt that by streching the oil changes using synthetic, the risk of sludge clogging is higher. So if you shorten the interval, you lose the benefit of the synthetic, and you're just blowing away dough.

He has a 500 Convertible.

He charges $35 per oil change. I'm not complaining.

Oh yeah, I once stretched the oil change on a Volvo 240 D. Interesting experience, when the bearings of the cam freeze, you snap the timing belt, etc...

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Henry Bofinger
1989 560 SEL (black/black)
2001 Audi TT Roadster (silver/grey)