I let them change it now with the 5w40 229.51 spec oil for 4 reasons

1) if it's good enough to keep a CDI clean for 13k miles, it's good enough to scour my m111 every 7500

2) You CANT buy this oil in stores

3) it's the highest-spec MB oil yet

4) It's $5 a quart retail AT THE DEALER. I haven't found Mobil 1 that cheap at Walmart, let alone from the dealer.

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former: 83 300D, 97 C230, 93 400E

current: 08 C300 Luxury , 92 500SL