Long story short, we don't seem to have a comprehensive "How to test the E39 pressure-controlled crankcase ventilation system (CCV)" on Bimmerfest; and the parts to order are scattered about, as are the descriptions & videos of what typically fails in the BMW E39 CCV system.
Since there are a billion CCV threads scattered about, our first goal is to 'summarize' all the known symptoms of a bad CCV & then the reliable known methods to test the CCV operation. (This is not intended to be a how-to-replace-the-CCV DIY.)
CCV synonyms:
- BMW-specific E39 acronyms
Note: This photograph of a BMW 530i CCV is from cn90, the original being here (Oil seperator).
Since there are a billion CCV threads scattered about, our first goal is to 'summarize' all the known symptoms of a bad CCV & then the reliable known methods to test the CCV operation. (This is not intended to be a how-to-replace-the-CCV DIY.)
CCV synonyms:
- BMW-specific E39 acronyms
- CCV = Crankcase vent valve, see also PCV, OSV, CVV, & CPV but not Clutch Control Valve (should be CDV)
- CPV = Crankcase pressure valve, the official name for the CCV, aka OSV, CVV, & PCV
- CVV = Crankcase ventilation valve, see also CCV, OSV, PCV, & CPV
- OSV = Oil separator valve, see also CCV, PCV, CVV, & CPV (not the same as the oil separator, OS)
- PCV = Positive crankcase ventilation, see also CCV, OSV, CVV, & CPV
- The intake manifold produces vacuum
- Blow-by gases produce crankcase pressure
- The CCV is simply a "middleman" controlled by intake manifold vacuum to maintain a slight vacuum under all conditions (1)
- The positive pressure from the crankcase is removed by the CCV which separates motor oil and combustible vapor (1)
- Oil goes back down the crankcase
- Vapor goes back into the Intake manifold
- The positive pressure from the crankcase is removed by the CCV which separates motor oil and combustible vapor (1)
- ? anything else ?
- The CCV sticks in the open position (1) due to the diaphragm tearing (2)
- The CCV hoses clog, causing pressure buildup, especially during cold weather & short trips (1)
- The CCV hoses deteriorate, causing vacuum leaks (1) (2) (3)
- Water freezes inside the CCV below -15°C cold starts causing misfires, hard starting, & blown valve cover gaskets (1)
Reputed Symptoms:
- After -15°C cold start, the engine misfires and stalls & will not restart (1)
- Oil filler cap is blown off
- Valve cover gasket leaks
- Occurs more often on short drives
- Blue smoky exhaust (1) (2)
- Some say a puff of smoke on startup (1)
- Brown sludge (1)
- Excessive oil consumption (1)
- Engine runs rough
- Whistling noise when you press on the accelerator (1) (2)
- Check Engine Light (CEL) or Service Engine Soon (SES) light on
- Possible DM faults stored: misfire all cylinders, oxygen sensor/mixture faults, etc.
- Vacuum leak at the dipstick lower o-ring (1)
- Too low or too high vacuum at the oil filler cap opening
- Pressure inside the crankcase (instead of vacuum)
- Blown valve cover gasket from excess crankcase pressure (1)
- Blown oil filter housing from excess crankcase pressure
- Dipstick blown out of its hole due to excess crankcase pressure (1)
- Some say vacuum holds down the dipstick (1)
- Hydrolock due to oil ingestion (1)
- ? what else ?
- Paper (or a plastic freezer baggy) over the warm-engine oil-filler opening as a visual vacuum test (1)
- Inflating balloon (or glove) over the dipstick as a visual crankcase pressure test (1) (2)
- Removing the CCV "Vent pipe" from the front of the valve cover while the engine is cold and blowing by mouth to hear oil bubbling (1)
- Manometer vacuum of 3"-6" of water at the oil filler cap opening (1) (2) (3)
- Look for a visible hole in any of the hoses
- ? what else ?
Note: This photograph of a BMW 530i CCV is from cn90, the original being here (Oil seperator).