Cooling System Drain and Refill

Operational monitoring of coolant
Before the start of the cold season, check the coolant for resistance to freezing.
In countries with high outside temperatures, check the concentration of anticorrosion/antifreeze agent once a year.
When topping up system (after loss of coolant, ensure that the concentration of anticorrosion/antifreeze agent in the coolant is 50 % by vol. to provide protection down to -37 °C.
The corrosion protection in the coolant is reduced during operation of the vehicle. Such coolant has a strongly corrosive effect.
The maximum permissible service life of the specified coolant in car engines is 3 years.
Before adding fresh coolant, flush the remaining coolant out of the system.

Disposing of coolant
Comply with legal regulations and local waste water regulations.

Draining coolant

1 Open cap of expansion tank in stages (coolant temperature below 90 °C).

Drain Plug, Model 107:

Drain Plug, Model 126:

2 Unscrew drain plug at radiator.

Drain Plug, Left:

Drain Plug, Right:

3 Unscrew drain plug at right and left of crankcase.

Filling Coolant





Expansion tank
Arrow = Coolant level cold

4 Fill in coolant slowly up to the mark on the expansion tank (arrow). Leave filler neck on expansion tank open.

Model 107
On vehicles with or without air conditioning system, set both heater levers to maximum heating capacity.
On vehicles with automatic climate control, pull off plug of electric supply line on heating water pump. Connect heating water pump to battery by means of self-made tool.
Push "DEF" button.

Model 126





On vehicles with automatic heater control, set both temperature dials to "Max".
Push "DEF" button on vehicles with automatic climate control.

5 Warm up engine by intermittently pressing the accelerator until coolant thermostat opens.
For this purpose, likely open vent screw (7) on engines 116.960 and 116.961 (AUS) (J) (S) (USA) 1981.

NOTE: Fit expansion tank cap at a coolant temperature of approx. 60 °C.

6 On model 107 with automatic climate control, refit plug of electric supply line to heating water pump.
7 Check coolant level and replenish up to specified level.

CAUTION: Open cap only below 90 °C coolant temperature.