I own a mercedes benz C200 CLASSIC. what is the best tell tale sign of the need...

[solved]

...for an oil filter/oil change? I owned a turbo diesel before, and i knew to change my oil when the oil turned black. what is the sign with a petrol engine. due for a service june 2008. any good weblinks? source? thanks for your time.

 

[Goldenrain]

Change the oil every 3 months or 3,000 miles, whichever comes first. You don't look for any sign, you just do it routinely.