啥是CCV:
Crank Case Ventilation Valve (Crank Case Vent),Crankcase Vent (CCV),Oil Separator - The crankcase vent is an oil separator that ensures oil mist generated in the normal functioning of the engine finds its way from the top of the engine back to the oil sump.
CCV故障特征(摘抄)：
The CCV also has two failure modes. The most serious failure mode occurs during sub-freezing temperatures and is the result of a mixture of oil mist and condensate (water) combining and freezing the separator solid so it can't do it's job. In the other failure mode the integral diaphragm in the CCV cracks and creates both a vacuum leak and a path for oil vapor to be sucked into the intake manifold and later burned. The result is usually a rough running engine and lots of blue smoke billowing from the exhaust. If this occurs it will most likely be associated with a check engine light (CEL) due to the vacuum leak and misfires that are the result of the contaminated fuel mixture. In a worst case scenario, if sufficient oil is sucked into the manifold the result can be a hydrolocked engine and a very large repair bill. For this reason I believe replacement of the $80 CCV is cheap insurance while you are under the hood.
When a crankcase breather valve begins to fail, engine drivability suffers. You may have a rough idle, hard start or a check engine light that is ON with fuel trim faults. If your engine is consuming oil or smoking, checking the crankcase vent valve is a good place to start. The crankcase breather has also been known to emit a honking or wheezing sound from the engine when failing. It is mounted to the back of intake manifold, near firewall. The crankcase vent hose that runs from the valve cover to the crankcase breather valve is the hose I find broken the most.
保養車型及原因：
2008 BMW 750Li E66 80K公裏， 90%是10-20公裏以內的短途使用，每年一次機油更換（不按裏程），目前車輛引擎運行狀況良好。
去年9-10月份開始發現在低轉速800-1000rpm之間有輕微不順暢，當時懷疑可能是機油品質惡化，於是同年11月更換的原廠機油，經過幾個月的使用，發現這種不順暢隻是變得更加輕微而不易察覺，但應該還是存在，於是判斷應該和機油品質及機油運行相關部件（油泵除外）有關，而與機油運行相關的兩個部件之一就是CCV，雖然也知道CCV失效的可能性很小，沒有燒機油和怠速問題，但終究已經有7年多和8萬公裏沒有檢測過，所以還是買了備用配件，一般我的原則是既然都打開了就不想再把舊的裝回去了，這樣至少10萬-8萬公裏以內沒必要再擔心這個部件了，也可以稱作是預防性養護吧！
作案難易程度：1/5 (5為最困難）
起因的原帖：關於'2008 BMW 750Li (E66) 換油及入冬保養作業'的一點後記
說了廢話一堆，還是看圖吧！
4顆10mm螺帽，介個XX蓋子就下來了，超級容易！
黃色實圈內藏著其中一個CCV,黃色虛圈顯示在這個黑側蓋下麵還有一個CCV,紅色指示的側蓋需要拔掉，沒有螺絲，隻是兩個扣壓件而已。
剝離軟橡膠防潮保護外衣，露出CCV
再來看另一麵
紅色是側蓋扣壓孔，黃色的就是另外的一個CCV
每個CCV蓋子有6個卡扣，這是特寫！
拆卸這個活兒的關鍵是要有合適的工具，這是一套在harborfreight買的專拆trim,bumper等塑料卡扣用的。
看了看還不壞，沒啥油泥和破損。
喜新厭舊的說，OEM的19刀一個而已（local BMW 38加刀一個）
擦了擦，不髒！
還是新的好看
安裝說明，6個clicks
逐個按壓，聽到每個click確認到位，6個哦！
其他的就是逐個部件複原而已，10萬公裏之內這個部件就屬於免維護了！
順便說，如果你的寶馬有所謂燒機油的問題，先查查這個部件，一來好整 二來便宜！排除了這個部件，剩下的估計你就不愛聽了，為啥？ 貴唄！滴樂對那個的報價應該在6000-8000刀:-( 啥芥末貴？ stem valve seals 唄！
周末有空換與機油相關的另一個部件： VANOS密封！
謝圍觀！
