My 2008 528I is displaying the symptoms of the bad ccv valve. Huge suction of the oil fill cap, rough idle, throwing codes for running lean due to vacuum issues (hopefully). I've had it for a few months and she's got about 82000 miles if I remember correctly. The ccv is integrated into the valve cover. Before I buy a new valve cover it seems like it might be worth trying to clean the valve and check the vacuum hoses for blockage. If the hoses aren't the problem, has anyone had any luck cleaning the valve with the cover off? I've looked around and couldn't find any info. Any help or links to related threads would be a god send. Thanks in advance. I'm not opposed to spending money to fix it, but I am opposed to spending money I don't need to spend to fix it.

 

Great question. Would also like to know if anyone has a cleaning solution.

 

We removed the cabin filters and air boxes to access the engine cover. I turned the car on to hear where the suction sound was most evident and there was zero excess suction sound. The oil filler cap was easy to remove as opposed to how difficult when it was sucking. Obd2 shows no logged faults but the engine light is yellow and won't clear. We put it all back together except for replacing the engine cover. A test drive showed that the car seems more lively than it has ever felt. I'm really boggled as to what was bumped, unpinched, moved during engine cover removal to change anything. Now I just need to get that light cleared and wait for any resurfacing symptoms to have something to fix.

 

Sucking sound is back, except not on the oil cap. She will be in the driveway until I get some time to sit with her. I've got A bunch of codes from the obd2 including a misfire in my cylinder 10. Tracking down my other four cylinders will be challenging.

 

Changing the valve cover tomorrow. It will be interesting to compare the function of the old cover compared to the new one. I'll try cleaning the old one up to see if it's salvageable.

 

I would say the part is not serviceable. even if you could knock stuff loose there would be no way to get gunk past diaphragms and the cyclone easily. If you get it off you might add well put a new one on. Depending what your time is worth, that is. She's working and that works for me. Total cost: $356+25 expedited shipping as well as 4.5hrs work. Bmw quoted $600-$700 plus 5hrs labor and incidentals and charge for diagnosis.

 

If I am not mistaken, 2008 528i has N52 engine. If so, function of CCV is performed by oil separator. It's located under the intake manifold. I'd investigate if one of the hoses connected to the oil separator is clogged. One hose goes from valve cover to the oil separator, another hose goes to the oil pan, and a thinner one goes behind the manifold (behind the throttlebody).