Pic. 149. Checking the density of the coolant: 1 — stopper of a broad tank
Before the onset of the cold season, it is necessary to check the degree of frost resistance of the coolant. To do this, open the cap of the expansion tank and take some liquid with a test device. The device shown in fig. 149, just one of many such testers. Other devices may use a rubber bulb for suction. On the scale of the device, as shown in the figure, or on the position of the float on other test devices, determine the density of the coolant and, if necessary, add the required amount of antifreeze.
Note. Mercedes recommends the use of only certain brands of antifreeze. In case of any doubt, contact the service station. This is especially important if the vehicle is still under warranty: non-recommended fluids can damage light alloy engine parts or the radiator.