Issue about 308 oil

[RosaStyle]

Hello, my 2014 308 1.2 turbo appears to be consuming an excessive amount of oil. Until recently, there were no issues, but now it seems to use more oil than anticipated—approximately one quart per 1,000 kilometres.Do you have any opinions? Many thanks

[Ledgerciao]

Reports indicate that the 1.2 Purecrap engine may have excessive oil consumption for two reasons. The first issue arises from the valve stem oil seals, while the second results from deteriorated oil control rings on the pistons. Pressure testing can determine the situation.

If the valve stem oil seals are defective, they can be replaced in situ using a method known as the coiled rope technique in the combustion chamber. I lack direct experience on this matter. Piston rings necessitate additional disassembly of the engine.

[CrownChikk]

The PCV valve may malfunction, and the baffles in the valve cover may become obstructed, allowing excessive oil to enter the air intake system as an additional potential cause. This may occur when fragments of a wet belt induce a failure mode, albeit it is not the sole cause of failure. This would be a more economical component to inspect or replace, and the aforementioned test would not detect this issue.

The PCV valve is typically integrated into the valve cover and may be serviceable; one can either clean the baffles or replace the entire valve cover, which includes the valve.
Examine the intake at the MAP sensor for excessive oil, or trace the smaller pipe (about 17-19mm ID) that connects the valve cover to the air intake and inspect the source.


The PCV system manages blow-by gases in the engine, and while all engines possess a mechanism for this management, it is particularly crucial in turbocharged engines, which generate greater blow-by compared to natively aspirated engines. The mechanisms employed for regulation include Positive Crankcase Ventilation (PCV), Closed Crankcase Ventilation (CCV), and Open Crankcase Ventilation (OCV), the latter of which is virtually obsolete under emission regulations, thus applicable only to vehicles manufactured prior to the 1970s or utilised in racing or off-road contexts where emission standards are not enforced.

PCV and CCV appear to be identical systems; however, the primary distinction in CCV is that the ECU must consider all the air. Your vehicle is equipped with a PCV control system, but only Peugeot diesel models utilise a CCV control system. The majority of diesel engines utilise CCV; however, certain models, such as Cummins, employ PCV control. On these engines, it is possible to install BOVs on the turbo without causing the ECU to malfunction, including stalling the engine due to unmonitored air. While BOVs are not essential for diesel engines, some enthusiasts appreciate the sound they produce.

[CrownChikk]

Compressed air can also be utilised on a regulator, through the spark plug port, to elevate the valves, typically for the purpose of replacing the valve stems. Similar to the apparatus employed for leak-down compression testing, this method is superior as it pinpoint the source of the problem. A compression test will just indicate the presence of an issue, which I believe you may be referencing with 'pressure tests'.

YouTube features films comparing 'compression tests and leak-down compression tests,' regardless of the engine type, if this piques your curiosity.

[CrownChikk]

You have not provided the kilometres travelled, the state in which it has been maintained (history), the type of engine oil used, or the distance between oil and filter changes, which are necessary for making assessments of its potential condition.

I trust you will find this beneficial.

[Ledgerciao]

I was referring to the leak-down test. I apologise for the improper designation.

I would be concerned about utilising compressed air to secure valves due to the potential for a disruption in the air supply. There is excessive risk involved for me!