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This thread is so confusing! To test, if I put a rubber inflatable device over the dipstick tube, am I going to get it to expand or contract? And why are there incorrect, if they are, diagrams here? And it seems different years had different hoses, correct? What is the simple test(s)?
 

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if I put a rubber inflatable device over the dipstick tube, am I going to get it to expand or contract?
Details here:
- How to test the crankcase ventilation (aka CCV, CVV, PCV, CPV, & OSV) pressure regulating valve system (1)


And why are there incorrect, if they are, diagrams here?
Ummm... because the diagrams are (slightly) incorrect. But, unless you want us to draw new ones, we're stuck with the incorrect ones.



And it seems different years had different hoses, correct?
They're mostly the same. AFAIK, the key difference is that the CCV itself looks different depending on the model year, and, the orange-and-black vacuum hose is not on the newer models.


What is the simple test(s)?
For my M54, I simply placed a plastic bag over the oil filler hole:
- Pictorial DIY for an M54 spark plug replacement on a 2002 BMW 525i E39 with 95K miles

 

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... stuff deleted ...

They're mostly the same. AFAIK, the key difference is that the CCV itself looks different depending on the model year, and, the orange-and-black vacuum hose is not on the newer models.


For my M54, I simply placed a plastic bag over the oil filler hole:

The balloon test over the dipstick tube can be useful since if you find any pressure (i.e. inflating balloon) the CCV has failed.
OTOH, I think the plastic bag over the oil filler is not precise enough to measure a failure on the too much vacuum side. From my experience it pays to do the test with accuracy - and pay attention to the results :).

For instance, I sarted getting a bit of a rough idle. I tried the baggy test & passed. I assumed the CCV was OK. Then I measured crankcase vacuum accurately & found 9 inches of water column vacuum; well outside the 4 - 6 inches specified by BMW. I knew the CCV was going south, but took a chance and hoped it would be "OK enough" until warmer weather arrived. A few months later I had ~45 inches w.c. (!) vacuum and most of the symptoms listed for a failed CCV. And weather around 0 F.:(

Here is a link describing how to measure CCV operation accurately, cheaply and in about 10 minutes.
http://www.bimmerfest.com/forums/showpost.php?p=5990442&postcount=8

Since there have been so many questions on the topic of CCV operation and failure, here is a description of how I think the CCV operates using Bluebee's picture for reference.

The vent pipe, swirl labyrinth chamber and vent hose are always at the same pressure or vacuum - there is no valve or obstruction between them. The swirl labyrinth is the lower part of the CCV assy that the vent pipe & vent hose connect to. Further, they connect to the valve cover & crankcase without restriction and are at crankcase pressure/vacuum.

The connecting line and return pipe connect to the inlet manifold which has a vacuum of ~20 inches Hg (mercury) at idle; ~260 inches water column vacuum.

The portion of the CCV immediately beside the blue "CCV" label in Bluebee's picture is a vacuum regulator whose job it is to maintain 4 -6" w.c. vacuum in the swirl chamber.

When the engine starts, the labyrinth is at 0 vacuum (i.e. vacuum is less than 4" w.c.) & the orifice/valve in the regulator is open. The gases in the swirl chamber flow through the regulator into the connecting line (which is at high vacuum), on to the inlet manifold and through the engine. Soon the vacuum in the swirl chamber (also the crankcase to which it is connected) is sucked down to 4 - 6" w.c. vacuum and the orifice valve in the regulator closes.

The engine runs, more blowby gases from the combustion chamber enter the crankcase & raise the pressure (reduce vacuum) in the vent pipe & swirl chamber. The regulator opens again, allows manifold vacuum in the connecting line to suck them away until crankcase vacuum is back to 4 - 6" w.c. at which point the regulator closes again. And on it goes, cycling over and over.

As the blowby gas travels through the engine toward the CCV, it picks up microscopic droplets/mist of oil. We don't want this oil mist to go through the vacuum regulator, into the inlet manifold and be burned: high oil consumption and air pollution. Enter the swirl labyrinth; it causes oil droplets/mist in the blowby gases to stick to the wall of the labyrinth and drain down the vent hose into the dipstick tube and sump while the "cleaned" gases carry on through the regulator.

Now the problems that ocurr.
One
One of the CCV hoses ruptures with age and lets air into the swirl chamber. The regulator stays open in a losing battle to get down to 4" w.c. vacuum. Lots of air is sucked in through the hole, on to the inlet manifold and the ECU senses a vacuum leak - bad news.

Two
The regulator diaphram ruptures with age. Now it can't close the orifice and crankcase vacuum goes high. And/or the rupture is so large that we have enough of a vacuum leak the the ECU gets upset. Plus gaskets and seals are being pushed harder than designed may fail entirely.

Three
The CCV and hoses can get very cold in winter conidtions since they aren't heated or even insulated. Blowby gases have lots of water vapour as a product of combustion chemistry. If these gases get cold enough, the vapour condenses into water and we get sludge/mayo. The mayo/water can freeze and block the regulator orifice - either open or closed.
Stuck open - high vacuum resulting in damaged gaskets/seals (or at worst, hydrolock according to BMW)

EDIT 2 - had this sentence in the "stuck closed" paragraph:
Also, seals and gaskets can start leaking air into the crankcase - a vacuum leak according to the engine.

Stuck closed - high pressure resulting in oil leaks &/or blown out gaskets and seals. BMW warns pressure can get high enough to crack the valve cover.

Four
Again in cold weather, water condenses in the swirl chamber, sludges it up so it can no longer separate out the oil mist droplets. Then, the blowby with oil mist is routed straight to the vacuum regulator into the engine. High oil consumption and in the worst case, hydrolock.

Five
Again in cold weather, the oil draining down the vent hose toward the sump plugs up in the narrow channel of the dipstick tube. Perhaps with some mayo/sludge if the regulator isn't operating properly (see above) to get all the water vapour out of the swirl chamber fast enough before it condenses. The liquid oil backs up into the swirl chamber, oil gets sucked through the vacuum regulator into the engine. In the worse case, so much oil the engine hydrolocks.

Three, four & five being good reasons for installing the cold weather CCV kit & insulated hoses.

EDIT: six
I occurs that if the CCV fails as above, oil mist and water can condense out in the distribution piece that the connecting line attaches to on the way to the inlet manifolc. One could then replace the CCV but have enough sludge in the distribution piece that a slug of it is pulled into the inlet manifold after the repair when the CCV is perfect. Bad news.
Seems a good reason for at least checking the distribution piece when doing a CCV overhaul.

Regards
RDL
 

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Dipstick tube vacuum...

Poolman,

Dipstick housing represents crankcase prssure, so it is almost always high from blow-by combustion. The dipstick can never suck in.

Vacuum exist in the Intake Manifold only.
cn90,

Actually I just did this test and I got definite, though very light suction at the dipstick tube and extremely heavy suction at the oil filler. Not sure what would cause this (dipstick tube vacuum) but I'm trying to diagnose a possible CVV failure.
 

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...

Since there have been so many questions on the topic of CCV operation and failure, here is a description of how I think the CCV operates using Bluebee's picture for reference.

The vent pipe, swirl labyrinth chamber and vent hose are always at the same pressure or vacuum - there is no valve or obstruction between them. The swirl labyrinth is the lower part of the CCV assy that the vent pipe & vent hose connect to. Further, they connect to the valve cover & crankcase without restriction and are at crankcase pressure/vacuum.

The connecting line and return pipe connect to the inlet manifold which has a vacuum of ~20 inches Hg (mercury) at idle; ~260 inches water column vacuum.

The portion of the CCV immediately beside the blue "CCV" label in Bluebee's picture is a vacuum regulator whose job it is to maintain 4 -6" w.c. vacuum in the swirl chamber.

When the engine starts, the labyrinth is at 0 vacuum (i.e. vacuum is less than 4" w.c.) & the orifice/valve in the regulator is open. The gases in the swirl chamber flow through the regulator into the connecting line (which is at high vacuum), on to the inlet manifold and through the engine. Soon the vacuum in the swirl chamber (also the crankcase to which it is connected) is sucked down to 4 - 6" w.c. vacuum and the orifice valve in the regulator closes.

The engine runs, more blowby gases from the combustion chamber enter the crankcase & raise the pressure (reduce vacuum) in the vent pipe & swirl chamber. The regulator opens again, allows manifold vacuum in the connecting line to suck them away until crankcase vacuum is back to 4 - 6" w.c. at which point the regulator closes again. And on it goes, cycling over and over.

As the blowby gas travels through the engine toward the CCV, it picks up microscopic droplets/mist of oil. We don't want this oil mist to go through the vacuum regulator, into the inlet manifold and be burned: high oil consumption and air pollution. Enter the swirl labyrinth; it causes oil droplets/mist in the blowby gases to stick to the wall of the labyrinth and drain down the vent hose into the dipstick tube and sump while the "cleaned" gases carry on through the regulator.
...
Regards
RDL
Great explanation RDL, but I disagree with one part of your analysis. I think the diaphragm in the CCV is operated by intake manifold pressure rather than crankcase pressure.

I cut a CCV apart and found a couple of interesting issues. First, the bottom part, which I call the cyclonic separator, and the top part, which I call the regulating valve are connected with a small tube. This is the tube with the vacuum nipple that controls the FPR on earlier models, This tube is hollow, but extends all of the way through the cyclonic separator and is the part to which the drain tube (vent hose) is attached. This tube is continuous from the regulating valve to the drain tube and is only perforated by a few slots just above where the tube exits the bottom of the cyclonic separator..

Also, the web inside the cyclonic separator is a continuous spiral. The outside of the spiral attaches to the cyclonic separator body at the entrance of the vent pipe. The inner part of the spiral web is attached to the central tube.

The central tube connects to the regulating valve on the same side of the diagram as connecting line to the intake manifold. Inside the regulating valve the diaphragm works in opposition to a spring on the vacuum side of the diaphragm. So the diaphragm that closes off the passage of gasses from the cyclonic separator is exposed to vacuum from both the crankcase and the intake manifold.

I think the intake manifold vacuum will always be higher than the crankcase vacuum. So I think the diaphragm opens when the intake manifold vacuum is lowered(is closer to atmospheric pressure) as the throttle plate opens. This mode of operation would route the blowby gasses into the intake manifold when engine speed is high and air intake volume is high.
 

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Great explanation RDL, but I disagree with one part of your analysis. I think the diaphragm in the CCV is operated by intake manifold pressure rather than crankcase pressure.
... stuff deleted ...

The central tube connects to the regulating valve on the same side of the diagram as connecting line to the intake manifold. Inside the regulating valve the diaphragm works in opposition to a spring on the vacuum side of the diaphragm. So the diaphragm that closes off the passage of gasses from the cyclonic separator is exposed to vacuum from both the crankcase and the intake manifold.

I think the intake manifold vacuum will always be higher than the crankcase vacuum. So I think the diaphragm opens when the intake manifold vacuum is lowered(is closer to atmospheric pressure) as the throttle plate opens. This mode of operation would route the blowby gasses into the intake manifold when engine speed is high and air intake volume is high.
I agree with much of your description but I think you misunderstand how the pieces are working together as a system. Whether the diaphram port is open or closed depends on vacuum in the CCV , not inlet manifold vacuum.

1 When the engine is started the CCV valve chamber is at atmospheric pressure, no vacuum.
2 The spring is pushing the diaphram away from the center port that is connected to the inlet manifold. So, there is an open passage from the crankcase, through the CCV to the inlet manifold.
3 The open passage allows manifold vacuum (engine now running) to suck air & blowby gases from the swirl chamber through the center port, eventually creating a vacuum inside the regulating valve chamber (and crankcase too, of course)
4 Now the diaphram will be pushed against the spring by atmospheric (higher) pressure on the other side of the diaphram. As the vacuum increases, the diaphram moves closer & closer to the port connected to the inlet manifold.
5 Eventually the diaphram compresses the spring enough that it touches the vacuum port and seals it off. This stops the inlet manifold from sucking any more from the swirl chamber. For an instant the vacuum on the swirl chamber is constant.
6 Next, blowby getting past the piston rings enters the swirl chamber & moves up into the regulating valve chamber which reduces the vacuum.
7 With reduced vacuum, the spring is able to move the diaphram and open the vacuum port to the inlet manifold again
8 Vaccum inside the chamber is again sucked down - around & around it goes.

So the vacuum in the CCV, and crankcase, is generated by inlet manifold vacuum and controlled by the CCV regulating valve. As long as the CCV is operating correctly, inlet manifold vacuum will always be greater than CCV/crankcase vacuum.

The size (diameter) of the diaphram, its flexibility/stiffness, strength of the spring and the relative position of diaphram & center port are worked out by the designer so that diaphram is just touching, i.e. closing off, the center port at a vacuum of 10 to 15 millibar (4 to 6 inches water column) in the CCV.

If my explanation isn't clear, try Wikipedia and Google for "pressure regulator" or "welding regulator" for a better description. The function is a little different than the CCV since these are reducing a high pressure to a lower working pressure. But the principal is the same: a diaphram or piston pushing against a spring is opening & closing a port allowing the gases to flow from higher pressure to lower pressure.
 

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6 Next, blowby getting past the piston rings enters the swirl chamber & moves up into the regulating valve chamber which reduces the vacuum.
7 With reduced vacuum, the spring is able to move the diaphram and open the vacuum port to the inlet manifold again
8 Vaccum inside the chamber is again sucked down - around & around it goes.,,,
This is where we disagree. As I recall, the vacuum from the intake manifold and the crankcase are applied to the same side of the diaphragm. I do not remember seeing any part of the diaphragm that was molded to fit the tubes or any sort of special port. Just a diaphragm that moves against a spring to close off those two ports. Anyway, I'll take another looks at the diaphragm.

BTW, I was thinking about measuring the vacuum that must be applied to the CCV to close the diaphragm. Have you done that or do you have any advice about how to measure the vacuum required to close the diaphragm?
 

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This is where we disagree. As I recall, the vacuum from the intake manifold and the crankcase are applied to the same side of the diaphragm. I do not remember seeing any part of the diaphragm that was molded to fit the tubes or any sort of special port. Just a diaphragm that moves against a spring to close off those two ports. Anyway, I'll take another looks at the diaphragm.

BTW, I was thinking about measuring the vacuum that must be applied to the CCV to close the diaphragm. Have you done that or do you have any advice about how to measure the vacuum required to close the diaphragm?
Yes, manifold vacuum and crankcase vacuum, or pressure, are applied to the same side of the diaphram. Except of course, manifold vacuum is blocked off when the diaphram moves far enough against the spring to touch the port connected to the inlet manifold. The port from the swirl chamber (crankcase) is never blocked. The diaphram isn't molded in a special shape to block off both ports. The flat center of the diaphram moves to touch or not touch (block or open) only the port in the center of the the regulator chamber which is connected to the inlet manifold.

This is the crucial point; crankcase vacuum (or pressure) is always present. Inlet manifold vacuum is "switched" on & off by the diaphram to control crankcase vacuum at 10 - 15 millibar.

Perhaps it will help to point out that when the diaphram opens the manifold vacuum port, crankcase vacuum does not instantaneously go to to full manifold vacuum. Rather it begins reducing crankcase pressure (increasing vacuum) as blowby gases are sucked into the inlet manifold. As crankcase vacuum approaches 10 - 15 millibar, the diaphram blocks the manifold port again, limiting crankcase vacuum.

So, the vacuum at which the diaphram closes off the inlet manifold port (i.e. center) is crankcase vacuum. See this thread for measurement methods
http://www.bimmerfest.com/forums/showthread.php?p=5989795#post5989795
Posts 7 & 8 suggest specific methods to measure this vacuum (or heaven forbid, pressure.:( )
 

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As someone who is currently involved with a redesign of the CCV, and studied the system extensively, I can tell you that rdl is 100% correct in his description of how the system functions. In fact it is by far the best technical description I have seen to date.

Good job.:thumbup:

Gary
 

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I looked at the diaphragm again. I can confirm that the diaphragm does indeed close off the vacuum to the intake manifold and that the crankcase vacuum is not closed off by the diaphragm when the the diaphragm is closed. I'll post a few pictures later today.
 

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As someone who is currently involved with a redesign of the CCV, and studied the system extensively, I can tell you that rdl is 100% correct in his description of how the system functions. In fact it is by far the best technical description I have seen to date.

Good job.:thumbup:

Gary
Do you know the pressure at which the diaphragm closes?
 

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I looked at the diaphragm again. I can confirm that the diaphragm does indeed close off the vacuum to the intake manifold and that the crankcase vacuum is not closed off by the diaphragm when the the diaphragm is closed.
I think we are all on the same page here. The diaphagm isolates the manifold vacuum (approx 260 inches of water) from the crankcase once the crankcase vacuum reaches 4-6 inches of water. The diaphagm modulates opening and closing the port to the intake manifold which regulates the crankcase vacuum to 4-6 inches of water.

Gary
 

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I think we are all on the same page here. The diaphagm isolates the manifold vacuum (approx 260 inches of water) from the crankcase once the crankcase vacuum reaches 4-6 inches of water. The diaphagm modulates opening and closing the port to the intake manifold which regulates the crankcase vacuum to 4-6 inches of water.

Gary
Thanks.

Here are two photos.

The first shows the opened vacuum regulator. This shows the diaphragm, the spring and the case. Note that the diaphragm seals off the hose going to the intake manifold, but does not seal off the central tube that allows gases to flow from the oil separator. The central tube and oil separator are at crankcase pressure.



The Second photo shows the oil separator of the CCV. I passed a red wire around the spiral to show the path of the gasses and show that it is a spiral. Note I drew the yellow line to show the inner edge of the spiral web on the oil separator. The oil and gasses enter from the left and travel along the spiral path until it reaches the central tube.

 

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Steve,

It looks like both pictures that you uploaded are the same.

I'm still a little confused as to whether you agree with me and RDL on how the system functions, or if you are still taking an opposing view. I'm not trying to be sarcastic in any way, I'm just not sure if we are on the same page yet.

Thanks,

Gary
 

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I'm here searching for a definitive way to test whether the steel CCV vent tube (integral with the oil dipstick guide tube) is clogged.

Mine was totally clogged recently.

I cleaned it out - but - how would I know when it becomes clogged again?
All the diagnostics I found were for testing the CCV itself, not for testing the steel vent tube.


BTW: I live in a warm clime ... where it (almost) never freezes ... and hardly ever rains ... so ... that tells me (almost) EVERYONE needs to check to see if their dipstick guide tube is clogged (unless they have a retrofit).

Q: Without removing it, what test, if any, will tell us the dipstick guide tube is clogged?
 
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