My fiesta rs has just begun smoking quite bad when i start up first thing then clears after a while untill i rev it then it puffs some smoke out whiteish / blue. Could a blocked breather pot cause this or could it be turbo or steam seals?
Cheers

 

sounds like stem seals matey

 

turbo mostly the t2 turbos crap

 

Does it smoke under load or just on start up and gear changes/revved after idling? If its the latter its more than likely stem seals.
I'd do them anyway, cheap and easy to do, even with the engine in place.