Engine has excessive crankcase pressure just after overhaul

SOURCE: crankcase builds pressure

if your blowing smoke out the pipe then the oil rings are bad , thus the pressure from explosion in the cylinder is going into the crankcase, which would mean the pressure rings are going bad also.
so you have loss of power also?
you should get it repaired soon or you could blow a gasket also and then it could crack the head or block
hope this info is worth a fixya , and if you need more assistance then just ask me and I'll help

SOURCE: oil is spraying out of the oil dipstick

Check the the PCV valve to see if it is clogged.

SOURCE: RENAULT LAGUNA 2.2DCI 2003 MODEL EXCESS CRANKCASE PRESSURE

This is quite a common problem,especially with the 2.2 dci engine,although as usual Renault wont admit the problem.The reason your engine throws the oil after a run and not when stationary is this problem is caused by the turbo pressurising the crankcase.You can rev the engine all day but when theres no load on it then the turbo is not working at full pressure and all is well.
The cure for the problem is to fit a new rocker cover which incorporates part of the inlet manifold.The breathing system on these engines is complicated and the rocker cover has to handle both inlet gases AND exhaust gases and although no one can explain why a new cover cures it,I suspect the plastic the cover is made of is not robust enough and either becomes porous or warped and this allows gases into the crankcase,pressurising it and focing oil out either through the dipstick or it blows out the blanking plug in the timing cover.
It is not a massive job to replace the rocker cover as long as the injectors come out easily.If they dont then youre in real trouble.Good luck,Duncan.

SOURCE: Oil leak passenger side 300 turbo sedan, some on

Add about 2.5-quarts of new engine oil to the engine.
Remove the passenger-side wheel, and support the car on jack-stands.
Start the engine and look for oil leak.
Chances are leaks are coming from failed oil-pan gasket or the drain-plug.
The head-cover gasket could be failing as well..