Service Intervals
WARNING: This page is about a different car, the 1986 Mercedes-Benz 300SDL, 1986 Mercedes-Benz 300E, 1986 Mercedes-Benz 300D, 1986 Mercedes-Benz 190E, and 1986 Mercedes-Benz 190D. However, it is still accessible from the selected car via links, so may be relevant.
Check fluid level every 15,000 miles. On 190D, change fluid every 5000 miles. On 190E, change fluid every 7500 miles.