Petrol engines oil emulsifying
Qu: I'm getting emulsified oil in my filler tube, is this classic head gasket leak?
Ans: No, probably not (Ed.)
Mocki: Symptons, overheating, emulsifying oil, overcooling
On the flat four WBX slight white gunge in filler is normal if you do short journeys in winter; aircooleds do it all the time. It's emulsified oil and the shape of the filler tube encourages condensation, and head gaskets on the WBX are not like inline engines, the oil and water rarely mix when they do go, most references to head gaskets "going" on these are really water jacket seals going, which result in air locks, which cause over heating, rather than oil and water mixing, and water dumping, or over pressuring, and chucking the water out of the top up bottle or blowing pipes off.
Keep an eye on the water level, in the header tank as well as the top up bottle, and the oil level, too, and most importantly the heater output, if it goes cold then hot then cold on your knee its airlocking, and the temp gauge may not show it, if it does it wont be at the same time as your knee feels it!
HarryMann: Long runs and making sure the thermostat is keeping ther engine up to temp in mid-winter will help minimise or avoid emulsification. Might as well keep wiping it out though!