Hi all,

I've ran into an issue with my 08 MCS. I believe what I'm hearing is a vacuum leak from the PCV hose...best I can describe it is "pshhh...pshhh...pshhh" with about a 2 second break in between. When it occurs, it makes my idle fluctuate. I see the PCV hose move slightly when it happens.
Also noting that when I try to remove the oil cap, there's quite a bit of suction.

Another issue I have is an oil leak. I've traced it back to the upper right side of the block (looking at it from the front), but I can't quite tell where it's coming from and I've ruled out the turbo oil line. It's a bit hard to tell since it's really gunky, but I have pictures below. Couldn't quite get in there since I can't find my toolbox anywhere, but did the best I could. I suspect the oil filter housing, but I cant be too sure because it's everywhere, but most of the "fresh oil" is to the right of the housing a bit if looking at the engine from the right side of the vehicle. Drips all the way to the bottom of the tranny.

Any help with these would be appreciated! Looking top down from the right side
To the right of the oil filter
View from above the oil filter. It's pooling down there.

 

Oil filter housing has two sets of gaskets --- check out the illustrated parts list http://www.realoem.com/bmw/enUS/select both are common failures. PITA to access and replace, but that's the best way to clean up the mess.

PCV system is supposed to create a crankcase vacuum --- the whole idea is to re-circulate the crankcase gasses to the intake manifold and burn them. Exactly how the PCV system functions is beyond me, but it shouldn't cause "idle surges". You might have a bad valve cover (PCV housing), but could also be an air leak somewhere. Also, if the valve cover has a crack or leaky seal, it could cause both "idle surges" and oil leaks.

Get more info before reacting to my input.

 

My Mini was leaking at the approximate same location where you described. I found out it was from from the vacuum pump and the oil pressures sensor. Mostly the vacuum pump though. They are fairly easy to change out.

 

Appreciate this. My oil pressure sensor has been a bit wonky lately (light comes on for a second at idle intermittently), so I'll probably be checking that first.

 

VHSNAP, did you ever get this sorted out? I have a 2009 MCS, with the excact same PCV issue and it's driving me nuts. I changed the valve cover gasket, new plugs, changed the oil, cleaned the Vanos and still have the small surge at idle. Car runs like a top otherwise. I'm throwing two codes; 2B64 ( Intake Manifold unmetered air) & 2970 (idle speed control in homogeneous mode).

Was not able to detect any cracks in the valve cover when I changed the gasket yesterday. I assume my next step is to do a smoke test to see if it's leaking.

Would love to know if you found a solution.

 

"Intake Manifold Unmetered Air" means there is more air in the intake manifold than went through the MAF, which is bound to affect idle speed. Possibly because of a loose hose clamp or maybe a damaged hose allowing air into the system. Yes, it could be something else but it's not always catastrophic. Smoke test is always a good idea.