Hi anyone interested!
Having searched all over the internet for advice and not finding much, now I have solved my issue I thought I would share it as it may help someone out there!
My problem was a blue smoke very smokey 307 1.6 hdi with excessive oil consumption. Smokey on first start up when cold which would clear a bit but blue smoke on power or when engine under load.
As expected, I first suspected the usual expensive suspects, valve seals, rings, turbo etc, and heard my wallet groaning. However on inspection I found excessive oil in the air intake pipe ( From mass air flow sensor to turbo),excessive oil at the cam cover PCV outlet, excessive oil at the turbo intake, oil in the intercooler and inlet and outlet pipes of said intercooler.
While it should be expected to see some light oil film from the crankcase breather system, whatever a peugeot dealer, mechanic, tech guy or your mate down the pub tells you, if you can dip your finger in dribbling oil in any of these areas in ain't normal!! Any more than a light film is too much.
What I discovered was that engine oil was passing directly out of the cam cover ( cover with the oil filler cap) via the PCV valve ( Breather opposite end of the cover from the filler) into the air intake system.
Almost another panic (as the PCV is integral to the cam cover and costS £100 ish) until i worked out how the PCV valve worked on this car. (postive crankcase ventillation) Breather system in plain english.
The PCV diaphragm is held in the closeD position via vacuum created in the air intake pipe via the small white branch connector attached to the intake and pushed into the cam cover. This diaphragm is held against a light spring pressure and is overcome by a crankcase pressure when need to vent out crankcase gases. The whole cover is designed to be an oil separator, allowing oil to return to the sump and vapour/gases to to be vented into the intake.
So to the issue..if there is not sufficient vacuum to hold the PCV diaphragm in the closed position, it will be constantly open and not doing its job, allowing excessive oily air to escape at its leisure from the breather into the air intake system.
The main thing (apart from the diaphragm) that maintains this vacuum is the O- ring on the air intake connector to the cam cover. What a pants design this is!! a nice pipe with two decent jubilee clips like most other engines would be better!
The replacement of the few pence o-ring to re-establish a good seal and get the PCV working properly solved this excessive oil burning problem!!
Of course I also cleaned out the inter cooler and all pipework affected.
Sorted my problem anyway, hope this helps someone, worth checking this little thing before a garage embarks on a process of elimination that costs you a fortune!