BMW E46 crankcase breather freezing in winter
E46 breather freezes in winter, what to do?
In a cold climate, an uninsulated breather system (CCV) is worth replacing with the cold-climate version. After freezing, replace the breather and the oil separator with original parts and the hoses with insulated winter-version hoses. Also check the valve cover gasket and the intake hoses.
What is the E46 cold-climate (cold country) breather kit?
The repair kit part number is 11617534237. It contains the breather and two insulated pipes (11617533398 and 11617533399). In addition you need a third insulated pipe, 11 15 7 532 629. The uninsulated kit comes by default, so ask for the right version by part number.
Is there a cold-climate breather for the N42 engine?
Yes. It belongs to option package S842A (Cold-climate version), which was on cars sold new in Finland. If the oil cap will not come off with the engine running when replacing the breather, there is a fault in the breather system, for example a hose fitted the wrong way round.