[335e92tx]

I was in the process of replacing my n54 (zf6) with a IS and got to reading on the DCT, it basically has a warmup circuit for the coolant. It runs it thru the radiator to get it up to operating temp quicker.


The M DCT transmission oil cooling circuit consists of an oil to coolant heat exchanger, an oil to air heat exchanger, a transmission oil thermostat and the relevant cooler lines. The oil to coolant heat exchanger is part of the engine cooling system of the vehicle. Mounted on the transmission housing it allows the oil to flow directly from the M DCT into the oil to coolant heat exchanger.
Engine coolant directly from the cylinder head is pumped to the oil to coolant heat exchanger by the auxiliary coolant pump and then circulated back to the engine cooling system. The M DCT electronics can switch on the auxiliary coolant pump as needed. The auxiliary coolant pump, which is normally used to enhance the efficiency of the heating system, is used here to warm up the M DCT transmission. This design shortens the warm up time and maintains the transmission oil in the desired operating temperature range.
After the oil to coolant heat exchanger has brought the temperature of the transmission oil to above 95°C/203°F, an oil thermostat directs the transmission oil to the oil to air heat exchanger located at the front of the vehicle.