After the 1st CCV failed in -60°F temps, I still have the WHOLE winter CCV setup working OK since February 2008. So, here is a testimony that the new dipstick guide works. That's on a M54B30 engine.

Catch can or CCV is the question....

I am still holding off on the catch can idea. There 2 (maybe 3) points of interest in this whole setup that put brakes on this project:

1. Low tension piston rings. Apparently A properly functioning pressure control valve is designed to maintain a slight vacuum (approximately 10 - 15 mbar ) in the crankcase which assures reliable crankcase venting during all engine operating conditions (this s very important)
2. A properly functioning crankcase valve. A PCV valve might not pull the trick. The PCV valve will open at a preset pressure and stay open until the pressure drops. Meaning that it can allow higher than 10-15 mbar? One could replace the OEM CCV unit with a Mann-Hummel unit, which has basically the SAME specs as the OE BMW CCV. The Mann-Hummel unit comes in 2 different flavors and each flavor has different sizes meant for different engine displacements. The 1,000,000 $ question is: will this unit also freeze? (Same principle / different design).
3. You have to stick with the SAME (or sensibly close) inner ID of the plumbing (it will wreck havoc with the required engine vacuum). I am still thinking on ways how to approach the CCV issue, and every time I thought I found the answer, I came to screeching halt by unforeseen issues. Maybe this is why Gary has trouble launching his CCV. For consistent inner ID, I found the OEM clamps sold separately, which in turn can accommodate the correct hoses for plumbing. I purchased a set from this source from E-bay . Here are some pics:

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Stable: e92is, e46 M54B25, e83 N52, e53 N62 - sold, e39 M54B30 R.I.P.