Ford Transit oil level keeps rising - why is it above maximum?

If the dipstick level on a Transit with a DPF, including the 2.2 TDCi from 2008 and EcoBlue engines, keeps rising, it is not producing oil; the extra liquid is diesel fuel. During diesel particulate filter regeneration, the ECU injects additional fuel. On short journeys, regeneration is repeatedly interrupted and unburned fuel runs down the cylinder walls into the sump. Oil diluted with diesel loses viscosity and its lubricating properties. On an EcoBlue with a wet timing belt, it also accelerates timing belt degradation. Oil above the maximum mark must not be left in the engine. Replace all the oil and the filter rather than simply draining off the excess. If the level rises again quickly, the cause is either journeys that are too short to complete regeneration or a DPF system fault, such as a failed differential pressure sensor or a blocked filter.