540i Howl noise from engine, rough idle, smoke on startup

[EuroFreak]

I noticed some engine oddities on my 540i/6 the other day and can't figure out what the cause could be...

Symptoms:
-When engine is slowing from 4k to idle, there is a loud howling noise coming from the left side of the engine
-Large puff of smoke on startup after sitting overnight
-Idle slowly fluctuates between 1300 RPM smooth to 800 RPM rough.
-Seems like it takes much longer for the engine to slow down than normal (takes a second longer to get to idle from about 4k)

Any thoughts on what this might be?

CCV? Oil separator? Vacuum leak? Does anyone have any ideas?

[EuroFreak]

Drove it again and realized there was quite a bit of vacuum at the dipstick tube so I am assuming its the CCV. We shall see...

[andershhDK]

What is CCV ??

[Gid]

+1 on CCV. Crank Case Vent

[EuroFreak]

There seem to be conflicting posts about what part is to be replaced on the 540i in the case that it is the CCV. Is the CCV also called the oil separator?

http://forums.bimmerforums.com/forum...1064179&page=2


Some point out that the rear manifold cover goes bad and needs to be replaced (#2 here: http://www.realoem.com/bmw/showparts...=11&fg=40&hl=5).

Others say its the oil separator within the engine (#1 here: http://www.realoem.com/bmw/showparts...55&hg=11&fg=15).

[jamesdc4]

There seem to be conflicting posts about what part is to be replaced on the 540i in the case that it is the CCV. Is the CCV also called the oil separator?

http://forums.bimmerforums.com/forum...1064179&page=2


Some point out that the rear manifold cover goes bad and needs to be replaced (#2 here: http://www.realoem.com/bmw/showparts...=11&fg=40&hl=5).

Others say its the oil separator within the engine (#1 here: http://www.realoem.com/bmw/showparts...55&hg=11&fg=15).

I PMed fijimon05 requesting an update on his thread. Hopefully, he'll chime in.

[EuroFreak]

Just a follow up... it was the CCV at the rear of the manifold. Its a ~$100 piece that looks to function as a typical PCV valve would. It took about an hour to replace as reaching the 6-8 bolts was a bit of a pain. It now runs perfect again.
For others who might have this issue in the future, you can reach your hand back there while the engine is running and feel for a vacuum leak... if there is suction, you need a new CCV. You'll also likely have suction at the dipstick tube.
One thing to note is to be gentle reinstalling this on the tube that runs to the front of the engine. If you force this back on, you could break the oil separator in the engine as it gets brittle over the years. And if you do that, have fun ripping the engine apart to replace. ;-)