How would I know if my turbo oil seals are leaky?
 

So I notice that I always get a cloud of light-greyish smoke when I rev the motor (under load - that is, the car is moving) to about 2500 rpm. This generally coincides with the transmission upshifting, but once my revs drop, the smoke vanishes too.

Should I suspect that my turbo is leaking? I can drive around sustained above 2500 rpm and I do not /think/ I see any smoke, but I need to definitively determine this.

Also - I never see smoke if I just rev in neutral.

Ideas?

That sounds like normal soot, not oil smoke. If your turbo seals are bad you will have high oil consumption and lots of blue smoke.

That's what I thought - just happens this is also my first Turbo (in addition to first diesel). I did just recently change my oil so I am tracking my consumption every time I fill. So far I've put about 350km on it and I might be down 1/4 of a litre.

How about oil in the tailpipe?