For filling up the system you will use 16.5 liters of special Green coolant type. You should be careful at choosing liquids for Mercedes-Benz especially for vehicles having 4.2 motor. For sufficient use of Mercedes-Benz 400 Series you need to use suitable antifreeze. In 1991 the company produced vehicles with 4.2 engine having code of M116.965. There is no chance 1988 400 Series engine will work efficiently with bad cooling.
Produced in 1988 the 4.2 engine in 400 Series model will serve longer by this. There is an important thing for M116.965 engines of Mercedes-Benz’s production – they expect good service. Better buy 16.5 liters of good antifreeze in Green color. So better use Mercedes-Benz’s advice for servicing 1989 400 Series.