Engine cooling - N16: Notes

The coolant pump is driven by a friction wheel, with a friction-gear servodrive fitted. This switches the coolant pump on or off. In general the coolant pump is always running. If necessary the DME can switch off the coolant pump by activating the friction-gear servodrive. However, this activation only ever takes place in the warm-up phase when no heater output is requested. Activation is stored in a characteristic map.