That sounds like a familiar problem,i've noticed my pipe is split where it joins the one way valve (UFO) thing,and I get a little bit of smoke now and again.I put it down to worn valve stem oil seals,and I'm about to embark on a full engine stripdown (both timing chains,new clutch,guides tensioners etc etc..) but after reading this I may try and change the hose first,and see what results I get.BTW mine is only on 82,000 miles,which I think is a bit low for worn valve stem seals! might be OK after all.