Lots of sludge under oil cap & on tip of dipstick. Thoughts please

[JStav]

My experience was exactly as the above post, still got the mayo for the whole of the winter a few years ago despite long runs. It cleared up in the Spring and never returned the following winter. I personally have a suspicion it was the quality of the oil.

Yeah like I say it's the white smoke bit that's worrying though.  Doesn't matter about the actual speed you're going it's under heavy acceleration you can see white smoke in the rear view mirror which surely can't be good 

I would be concerned with this if the car is using water, if not then it could be concentration in the exhaust or more likely condensation in the air caused by the sudden release of lots of hot gases into the cold air when you accelerate hard.

By water do you mean the coolant?    The coolant light came up notifying me i needed to top up the coolant but this was around 3 months ago, and the level doesn't seem to have dropped since then, so a bit puzzled!

[jbc]

Yes I mean the coolant. If you needed to top up the coolant previously then it must have escaped somewhere, which is concerning. If water had escaped through the head gasket into the oil it wouldn't suddenly stop so the two arent necessarily connected.