Low outside temperatures

DEF freezes at a temperature of approximately 12 °F (–11 °C). The vehicle is equipped with a DEF preheating system when it leaves the factory. Winter operation is therefore also guaranteed at temperatures below 12 °F (–11 °C).

    See also:

    Safety
    The R-Class received a Good overall score — the highest rating possible — in the Insurance Institute for Highway Safety's frontal-offset and side-impact crash tests. It hadn't yet undergone IIHS' ...

    Purity
    Assuring the purity of DEF is particularly important with respect to avoiding malfunctions in the exhaust gas aftertreatment system. If DEF is pumped out of the DEF tank, e.g. during repair wo ...

    M+S tires
    At temperatures below 45 °F (+7 °C), use winter tires or all-season tires. Both types of tire are identified by the M+S marking. Only winter tires bearing the snowflake symbol in addition t ...