2006 Focus MK2 1.6 (Petrol) losing oil

[Azurren]

Hey guys

So I've been trawling through these forums however so many different models / variants are covered it gets somewhat confusing tracking down people who've had similar experience with the same model of car. I have a 2006 Ford Focus MK2 1.6 petrol which is losing oil.
About 1 liter every 2k miles (2 months), but this is sporadic.

My round commute is 56 miles, mainly dual carriageway miles however even though my driving style is fairly consistent oil loss is not. It won't move for weeks then it'll loose a visible amount in a few days. There is no visible signs of leakage, no obvious blue smoke from the exhaust and so noticeable decrease in power or fuel economy. 

Is there anything simple I can check before assuming the worst? I've tried looking for the typical PCV valves but can't find the part online or in the engine bay (does the mk2 1.6 petrol focus have a PCV valve?)
I've also removed and cleaned the breather hose running from the top of the engine to the air filter assembly (was a little oily but not clogged in anyway)

Any help at all would be greatly appreciated, even if it's just a push in the right direction / a link to another forum post.
Thanks!

[nazsky786]

There is a pcv valve located just behind the inlet manifold on top of the oil separator. The 1.6 I had was putting oil into the airbox. I changed the pcv and it sorted the issue. Also you need to check oil when cold and check when warm. The 1.6 is a weird engine. Oil just disappears only to come back later, and if you fill it up thinking it's empty you over fill causing these issues also. 

[mjt]

6 hours ago, nazsky786 said:

Oil just disappears only to come back later, and if you fill it up thinking it's empty you over fill

I have a theory about this and it's related to the 'o'-ring on the dipstick. This forms a seal at the top of the dipstick tube. When the engine is running the level drops as oil is pumped around and that allows air into the tube, at crankcase pressure. When the engine stops the air in the tube prevents the oil rising up it so if you just pull the dipstick it appears the level is low. Once you've removed the dipstick, thus releasing the airlock, the oil will rise up the tube so if you dip again oil will magically reappear.

Of course this would only work if the tube is at least as long as the dipstick and I've no idea if this is the case but it seems a plausible explanation.

I think it's actually recommended to dip twice for an accurate reading.

[btmaldon]

As MJT says. You must pull the dipstick, wipe it then put it back in before checking the level for that very reason.

[Azurren]

Thanks for the replies guys!

On 8/5/2016 at 2:15 PM, nazsky786 said:

There is a pcv valve located just behind the inlet manifold on top of the oil separator. The 1.6 I had was putting oil into the airbox. I changed the pcv and it sorted the issue. Also you need to check oil when cold and check when warm. The 1.6 is a weird engine. Oil just disappears only to come back later, and if you fill it up thinking it's empty you over fill causing these issues also. 

Indeed I have noticed this. I didn't mention it because I didn't think anyone would believe me that the oil level does fluctuate up and down at times but even so it is loosing it over time.
Which is why I've only been topping it up from just below the min mark to the half way line

Do you have a link to the correct PCV valve for this engine? I've only been able to find PCV valves for the 1.8-2.0 liter models.
Also can it be swapped out with the inlet manifold in situ?

Cheers!