I don't know if this is the correct place for this question but I'll post it anyway. Before I read about Flying Tiger, I bought a used smart and decided to take it for an oil change as I did not know when the previous owner had done this. So, I took it to a Mercedes dealer and paid just over $300 for a B service and a brake fluid flush. I decided to check the oil level a few days later as I had read that irreversible damage could be done to the engine if the oil level is too high. The oil was black and like syrup so I went back to the dealer and enquired about this. The technician said that this was normal for a diesel engine. Could you tell me if this is so. Thank you very much for your help.