Does not have PCV - pretty unlikely as not seen any Peugeot Diesels with them to date. So let's talk generally and see if helps you out because don't have this model details to look at.

It does have / likely to have, an oil decanter system and/or CCV. You can find it by looking for a small hose usually about 19mm ID diameter, connected to air intake before the turbo follow it back to where it connects on the valve cover and at this point you have found the CCV or an oil decanting system.

The CCV may be a serviceable item, or might be part of the valve cover an oil decanting system / which is a baffle type system or both.
Post photos once you find it, and might be able to tell you about what it is or isn't.

Very few diesels will have PCV system (some Cummings do have them, some Ford diesels), nearly always a CCV type system. They can look similar, near identical to PCV system, hence the confusion or mixing of the terms, why it muddies the subject, and I will explain why.

PCV - Positive crankcase ventilation system. The ECU does not need to account for all the air in this system. IE: An external BoV will work or could vent the PCV to atmosphere.
CCV - Closed crankcase ventilation system. The major difference is that ECU must account for all air, for this type of system. IE: You can't use BoV unless internal type, and cannot vent to atmosphere without the ECU will have big trouble. Feel like turbo lag or just pauses when you said go go go, usually on slight incline when air leak exists in ones of these systems.

An oil decanter (baffles in the valve cover can be used on their own, but being turbo / blow by gases / suggest it still likely to have CCV) can be used on either of these systems, but PCV or CCV may be incorporated into this, or be separate. Peugeot is mixed across the ranges, and would not like to guess.

You can check CCV function by open air intake or the air doser for the amount of oil / looking for excessive / there will be oil. If awful, need to check intercooler, it will pool in there, but normally see smoke associated on full acceleration or inconsistent boost issues on full acceleration as symptoms (which also can be an air leak or other issue).

The PCV or CCV is normally a fancy name for a check valve that is either metal / spring, or membrane / spring but not always this, there are other versions but rarely.

If was say, a turbo bearing, normally leak into the exhaust, and you would see smoke from the exhaust, typically, but can check at intake for lateral movement in the impeller shaft (any is bad) or if the nut on the impeller (assuming has one) has undone, would be a strong sign the turbo is done.

If got nothing happening here, suggest leak down compression test, because helps identify problem and source of issue with compression. Can identify weak valve stem seals or compression rings, for example. Won't always identify a weak oil control ring, but likely too, and better than standard compression test which only tell you have a problem at best. YouTube should have side by side examples, on any engine, of these two tests, and why the leak down compression test is more useful and more likely to detect faults than a standard compression test.

Hope you find this useful.

 

I would remove the engine head and cylinder block and send it to repairs. Otherwise you can also check if there are any leaks of oil on engine outer surface. I doubt it can leak that much though. Engine probably needs an intensive repair.

 

Thanks for your replies @RedSector & @MaskedVigilante and sorry for my delay.

I've had to top up with 6ltrs in just over 3 weeks. No real signs of any major leak on the floor (very minimal drip at times) and I've got no smoke coming out the exhaust.

Engine performance had been fine, up until about 2 days ago. Now I'm starting to notice a big of 'lag' in acceleration when I go to pull away. Could all this be linked and does that point to what might be the cause?

Here is a photo of my engine bay, are you able to point out to me here I should be looking for the things you mentioned in your reply

Thanks again.

 

The CCV is built into the valve cover, appears to be a baffle system, does not appear like it can be changed without the whole valve cover. Any air leak after the MAF and before the turbo will cause an issue like you described, and typically will not throw a fault code (DTC). There is o-ring on the dipstick worth trying replacing that as well.

Proper diagnostics with Lexia or equal device may shed light on the issue, for DTC or via live data. In live data, an air leak will show ECU doing consistent positive trimming of the injectors at idle and higher. A system which knows air volume in, will be negative trims or switching between negative to positive fuel trims at idle. It is possible for this to indicate a problem with MAF or MAP sensor, but not likely without DTC. You could also try cleaning (petrol or other solvent works) the MAP Sensor, which appears like might be, the blue marked sensor, near the dipstick (orange coloured).

A blocked air filter could also cause similar described issues, but I am assuming basic maintenance points have been checked off.

Hope you find this useful.

 

The only source for information on this engine is likely to be Peugeot Service Box (servicebox-parts.com) this is because in DEC 2013 everything was put behind this paywall, and few have complete access or willing to pay for access simply to provide information. Models up to 2016 might be covered by DEC 2013 VM of servicebox, but not likely after that.

 

I have done a few of these. There is a small mushroom type valve that sits in a recess between the head and block. I think it stops oil vapours entering the head then into the intake pipe and through the turbo and burnt in the combustion process, hence why no sign of smoke or visible oil loss. I think there was a batch of engines that had a defective valve fitted . If you buy one through peugeot now it has been modified.. it only costs a few quid but needs an engine strip to fit and probably snapped head bolts ! But thats another story !!