Blue smoke on startup w211 e320cdi

[mattc]

Have noticed a bit of blue smoke (defo blue not grey or white) from Nat's car on start up. Seems to clear immediately. It's a 2004 with 94k on the clock and comprehensive history.

What's the most likely causes please? Valves seals, leaky turbo. Want to nip it in the bud if possible.

 

[ET4]

Blue smoke is usually engine oil.
It could be valve stem seals, you can check by seeing if it smokes on overrun. Stick it in second and drive at high revs for a bit then take your foot off the accelerator. Normally smokes blue as the revs drop.