All-weather oil must be used for BMW engines. Multigrade oils have the advantage that they operate over a wide temperature range (summer Winter). The basis of all-weather oil is a grade of liquid oil (e.g. 15W) Thanks to the so-called hot thickener, the oil is stabilized, thus retaining its lubricating properties under all operating conditions.
Letter "W" in the SAE designation indicates the suitability of the oil grade in winter.
Light-running oils are multi-grade oils with an additive that reduces internal friction, which can save up to 2 percent in fuel. Lightweight oils have a low viscosity (e.g. 10 W-30). Unusual oils are used as base oils here (synthetic oils). When buying low-speed oil, you should pay attention to the OPEL approval (written on the label).