1996 E320 Oil change

[Machnumber2]

I have a Mercedes E320 1996. I was just wondering what type of oil should be used for an oil change. The dealer last year indicated to use synthetic oil and that you did not need to bring it in until the dash indicated it was time for an oil change. Its been well over a year and 10,000+ miles and I still have not seen that message. We called an independant shop and he quoted $65 for oil change, when asked he didnt seem to know about the synthetic oil or the fact that this car senses when the oil needs to be changed and tells you.

I dont even know now if the car has an oil sensor that lets you know when to change the oil or if you should only use synthetic.

Any thoughts would be welcome. We love this car and want to take the best care of it we can. We stopped going to the dealer after they quoted us $1000+ to replace the fuel pump which seemed excessive.