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This is my first post, I just wanted to clarify the operation of the ccv valve (this applies to the 5 and 3 series as well.) I've read many posts in the past on how to tell if yours is bad and how to replace, but I thought I might share a little info that will help with vacuum leak diagnostics when the ccv is in fact good. I see the problem quite frequently in my shop..............]

Very good information regarding CCV system!

Here is my question:
My 2005 X5, 4.4 (N62), 83K, started to comsume oil recently, I inspected the CCV, one of the rubber seal is harden, could not seal properly. and replaced both of them ($25/each from dealer, Parts# 11 12 7 547 058). The engin runs very smooth.

After reading all of these posts here, I made a pressure gauge to measure the vaccum in crankcase. It is 10 in of water.
Read other post, said it should be around 5" of water.
And I block one of vaccum hose from intake to CCV, pressure still at 10", and blocked the other one, it is same.

It seem to me that booth new CCV works properly and regulate the vaccum at 10" of water.

Question: Is this N62 engine, designed to higher vaccum than others? Or this new design of CCV regulate the crankcase pressure at the high vaccum?

Also, it seem to me that the CCV is pressure regulator, it is not an on-off shut valve, rather, it continous open all the time with different flow per the force pushed on the valve seat, the higher vaccum at crankcase, the higher force to overcome the spring to reduce the gas flow rate.
This would regulate the crankcase pressure at pre-set level (set by the spring force of the CCV).

Any input would be appreciated
 
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