I had a 2002 BMW 325i that i drove for a very short commute time in -20c to 0c. That resulted in a $2000 repair bill for a $70 dollar part.
To keep it short, as your engine warms it creates condensation = (cold block + combustion heat). When you reach optimal operating temperature, a valve opens PCV or CCV in a BMW and allows this moisture to be circulated into the combustion chamber, Viola no moisture in your oil.
But when you don't reach optimal temperature each time your creating moisture in the motor and engine oil. Since oil change intervals are so long you get a high moisture content. When that moisture surrounds a rubber membrane = CCV valve and freezes it tears and clogs that valve.
Go to e46 look up CCV valve, so look under your engine oil cap white film = moisture!