So I have a (new) Used 2011 Mini Cooper S. Car runs great, starts easily, idles fine, no codes, 64K. After I bought I changed the oil, replaced the plugs, the coils, new HPFP, new Fuel Filter. However, since my oil change, I've put 500 miles on it and it was a 1/2 quart low. After another 400 miles, it looks to be another 1/2 quart off top. So that is 1quart for 900 miles. That seems like a lot of oil use to me.

I'm running 5w-30, Castrol, Full Synth. I see no oil leaks under the car, around the valve cover or anywhere obvious (yet). No smoke out exhaust after startup.

There are articles that say a bad PCV valve causes excessive oil consumption. https://www.yourmechanic.com/article..._source=impact



My question is even though my PCV value is working and there are no codes, is it possible that a weak PCV valve is causing more oil by-pass into my turbo and intake and thus more than normal oil is burning up?

 

Yes it’s possible that the diaphragm in the valve cover is torn. I have a thread about replacing it to save about $400 here.
https://www.northamericanmotoring.co...-question.html
Is there oil residue around the semi-circular cap on the left rear corner of the valve cover?

 

I have no MINI experience but I had 3 AOSs (Air/oil separators, which is also the PCV) go bad on another car, about once every 100K miles, and the late stage failure mode was a heavily smoking engine, the valve that normally would close under engine vacuum was not working right because the reinforced diaphragm had failed -- developed a "hole" due to material fatigue -- and subjecting the engine crankcase to full engine vacuum. It was so bad that in one case while I could unscrew the oil filler tube cap with the engine idling I could not remove the cap against the pressure difference.

Other owners have reported a squeal/moan as air leaks past the engine main seals

 

No oil or oil residue anywhere in the engine compartment. I cleaned it and nothing has returned. The only oil residue I see is under the oil filter but it looks really old. I just couldn't reach down there.

I found a new PCV replacement on eBay for $10. I will pull the old one off and if it even looks "half as bad" as the one you posted in that other thread, I would say he needs to be replaced. :P
If its dirty, I clean and use it as a spare if I'm wrong.

My car gets 30mpg mixed-use though....It's just burning oil like a car with 120K with a trail of smoke out the back.

 

Would that be the same part for the non-turbo cars? If so, I may try it too. My car uses about a quart every 1K or so as well... have been thinking i needed a new valve cover etc... Let us know how it works.

 

I have an R-56 N18 engine. Someone figured out a way of just pulling it up in the top left of the valve cover. I think if you have the one just before you have to get the whole valve cover.

https://www.ebay.com/i/362702116994?...26pg%3D2386202

 

It seems strange that the OEM cure to the problem is to replace the entire valve cover when this item looks more as regular maintenance.

Anybody asked Mini what this is about? I am furthermore surprised it could happen at about 60K.

 

There are a couple of other one-way valves in there that can clog up too. But usually it’s the diaphragm.
The non-turbo Justa models use a different diaphragm, iirc, but they are available and get replaced the same way. I had to get mine from Russia, but there are more local ones you can get now... maybe even from ECS now.

 

Also like mentioned above, a good way to tell if it’s not leaving residue or whistling, is to try to remove the oil filler cap when it’s running. It shouldn’t be very hard to pull out, if it is, it’s getting vacuum and the diaphragm is probably torn.

 

Tell me about it. I jest that they promoted the original designer of the valve cover/PCV valve combination to design the 3rd gen Minis's but don't tell any of them as they are thin skinned.
See this article that says you should inspect and replace your PCV valve at regular major service intervals.
https://www.yourmechanic.com/article...pcv-valve-last

That's with a normal mechanical PCV valve that likely will go much more than 60K. The Mini designers didn't just put it in the valve cover, they designed it out of rubber which is typically not good for temperatures over 250F.

So I would just say the whole thing is a very bad design.

 

So this is describing a complete failure. What if it sticks or is completely fatigued but is still technically working? I mean supposedly this car with go 10,000 miles without an oil change or a new oil filter. I guarantee looking into my valve cover, the previous owner did try this at least once.

I think the Russia ones that I saw looked to be "much better designed" and "much better quality". The cheaper one's from China I show on eBay above are not as good as the Russia ones. However, I would make this a routine part of every 5th or so oil change.

 

Yeah mine was pretty torn up when I really looked, but at first it looked ok. They can get some really small holes in them that are hard to see but cause the same issues. The I got is still going just fine, so I cannot complain about it. I know what Mini says, but I would not go more than 5k for oil changes. That’s part of the turbo problem, from what I’ve read. The oil gets coked up in the line. Good luck!

 

I replaced mine. Getting the cover off was a bit tricky as you are totally working in the blind. I had to tighten the belt on my pants a couple of holes, but it eventually came off, then the spring popped off and landed inside the compartment where I could fish it out.

The PCV membrane really didn't look that bad. Picture below. Mine was melted in a couple of places on one side where it seals. However, under the pressure of the spring and cover, it was probably sealing ok. Now, the whole inside was caked with burnt oil sludge that took on the appearance of hardened grease like a coked intake. It took me an hour to clean that up with rags. The spring had the same coked oil on it. After cleaning everything up, I put a light coating of fresh motor oil on everything so that it sealed good and put it back together. We'll see if it does anything for oil consumption. Based on the looks of the membrane, I would say no, that's not the problem.

 

In my experience of rebuilding an N12, the biggest culprit to excessive oil consumption is the factory fitted 'one-piece' oil control rings. Before the rebuild my partner's N12 was sucking 1 litre of oil out of the sump very 800 miles. After replacing the oil control rings with '3-piece' oil control rings, oil consumption went to zero. Now I did replace the valve guide seals on earlier head work and didn't really see a whole lot of improvement. Conclusion I have come to is that you have to get the head off, sump off, piston assemblies out and replace stock rings for a better set. No liquid magic or rubber/PVC fetish is going to fix this problem.