Any pressure will become evident as soon as the engine is turned on--what they are pointing to, is that
the pressure to just partially inflate the balloon is evidence the pvc system needs work.
I would guess that when trying this procedure on our cars--if the ballon trys to be sucked into the
dipstick hole just a little that all is OK--if it's being sucked in at a high rate though the ccv could be going bad.
..if the ballon trys to be sucked into the
dipstick hole just a little that all is OK--if it's being sucked in at a high rate though the ccv could be going bad.
On the VANOS repair site (Rajaie) posted this trick
"The crankcase vent valve and 4 associate hoses fail and cause a vacuum leak. The valve gets stuck open and the hoses crack. These last 70-120k miles and usually fail 80-90k miles. Here are a couple diagnoses.
At warm idle, place a small plastic freezer storage bag on its side over the oil fill hole. If the bag sits on top or gets slightly sucked in, ~1***8221;, the valve is good. If the bag gets significantly sucked in the hole the valve is stuck open and bad.
With the engine off and cold, carefully remove the hose at the valve cover front corner. Blow hard into the hole. You should hear oil bubbling in the oil pan. If you don***8217;t hear the bubbling the top or bottom hose is likely cracked. The bottom hose often breaks just below the valve connection. There can also be cracks in the other two hoses."
On the VANOS repair site (Rajaie) posted this trick
"The crankcase vent valve and 4 associate hoses fail and cause a vacuum leak. The valve gets stuck open and the hoses crack. These last 70-120k miles and usually fail 80-90k miles. Here are a couple diagnoses.
At warm idle, place a small plastic freezer storage bag on its side over the oil fill hole. If the bag sits on top or gets slightly sucked in, ~1", the valve is good. If the bag gets significantly sucked in the hole the valve is stuck open and bad.
With the engine off and cold, carefully remove the hose at the valve cover front corner. Blow hard into the hole. You should hear oil bubbling in the oil pan. If you don't hear the bubbling the top or bottom hose is likely cracked. The bottom hose often breaks just below the valve connection. There can also be cracks in the other two hoses."
This bag trick is messy on the 540i because the oil fill location is on top of the timing chain, which when the engine is running will whip oil through the oil fill hole. I think the ballon trick would be best for the V8's.
Not sure who is right here but Gtxragtop (Dave) did a test on my dipstick tube to determine CCV function by measuring the amount of vacuum pulled (I can't remember but I think the proper amount is 3"-6" of water). Not sure where this test came from (TIS?). No/low vacuum meant a CCV problem. My understanding is this test measures the amount of vacuum in the crankcase. But I am not sure how the pressure in the sump translates to the pressure in the crankcase. According to this test, the sump should have negative pressure and pull on the balloon, if the CCV is functioning properly. If it inflates the balloon, there is definitely a problem as that would indicate positive pressure in the sump. In addition, positive pressure in the sump should also blow the dipstick out of the hole. In theory the CCV is supposed to keep the crankcase from a positive pressure condition and that a failed CCV will create a positive pressure situation by keeping the crankcase from venting gases. If I sound confused, it is because I am. :dunno: All I know is that I replaced the damn thing and I have stopped burning oil.
In a nutshell, the crankcase always produces pressure from blow-by. The CCV is simply a "middleman" controlled by Intake Manifold Vacuum.
This way the positive pressure from the crankcase is removed by the CCV which separates oil and vapor:
- Oil goes back down the crankcase
- Vapor goes back into the Intake manifold.
This is why the CCV is also called "Oil Separator" in the Volvo language.
Got most of that. Someone correct me if I am wrong. I refer to the real.oem diagram for the CCV. The oil and vapor from the cylinder head (positive pressure) goes into the CCV through the vent pipe (2). The CCV "separates" the liquid from the vapor and returns the vapor portion back into the intake manifold (negative pressure) using the connecting line (3) and the return pipe (7). The liquid oil condensate flows back into the sump via the vent hose (4).
If the previous is correct, is the sump at negative pressure, ambient or positive pressure? The dipstick vacuum pressure test suggests it is at negative pressure.
I ask because my previous e39 (which Gtxragtop tested) tested OK for negative pressure even though the car demonstrated some of the classic symptoms of CCV failure (oil consumption, burning oil, etc.). My current e39 appeared to burn oil (occasional black exhaust smoke in cold weather) but was never tested. I changed the CCV and that has gone away. It would be great to have a reliable test to verify proper CCV function as it is a PITA to change out. At this point, I am not so sure the dipstick vacuum test is that reliable of an indicator.
1. "A" is the crank case pressure. It is the same whether you measure it at the Top Valve Cover Outlet or the Dipstick because the Top part of the Engine Cam Lobes area connect to the sump via some air channels (this is how crankcase air goes from the sump upward into the cam lobes area).
2. "B" is the Intake Manifold Vacuum.
The following numbers are arbitrary just to illustrate the concept.
Sea level air pressure is 760 mm Hg or 14.7 psi. But let's set this as zero as a point of reference purpose.
And let's say the CCV is designed such that when there is a differential of 3, it opens the spring allowing vapor to return to the I.M.
Scenario A: car warm and idling at 700 rpm:
- Atmospheric air "zero"
- Intake Manifold vacuum = "- 1"
- Crankcase Pressure: goes slowly from "1" to "3" (from blow-by)
At "-1" and "1", the difference is only 2, so the CCV is closed, but at -1 and 3, the difference is 4 so the CCV is open allowing vapor to return to the I.M. At the same time, liquid (oil) is allowed to flow back down the crankcase drop by drop (basically dripping, not a full flow).
Scenario B: you are driving at 3000 rpm:
- Atmospheric air "zero"
- Intake Manifold vacuum = "- 3"
- Crankcase Pressure: goes slowly from "3" to "5" (from blow-by)
In this case the CCV is always open because the min difference is still 6.
Maybe one of us can get a birthday balloon and play with it this weekend and report back (assuming your CCV is fine)?
Hi Cam,
Looking at this diagram (to figure out how the CCV works), did I draw the directions of the pressure (orange) and vacuum (yellow) in the M54 engine correctly?
Notice you do not show the direction of the thin line called "vacuum hose", so I 'guessed' at which direction the flow is going.
Likewise, the Realoem diagram for my M54 engine seems to have the "return pipe" reversed, so, that adds a bit of confusion.
Can someone correct this diagram so that we have the correct directions for the M54 CCV?
CN90--don't know about you M52--but my M54 has always had vacuum at the dipstick as well as the valve cover oil cap--on the later engines there is a vacuum directed into the crankcase via the valvecover gasket
the oil dipstick tube has two different channels in it to allow oil to drainback and the dipstick itself.
One of the big problems that must be watched out for when doing the ccv valve work on the M54 engine
is to make sure the dipstick tube 0 ring is seated properly when doing the reinstall and ensureing there isn't a vac leak there. Vacuum is introduced into the crankcase from the distribution unit--then to the ccv and from there to the valve cover.
The crankcase, valve cover, dipstick tube are all connected by wide open space. Remember, the oil on the camshaft has to drain back down to the sump. According to the TIS, the vacuum should be between 3-6" of WATER no Hg (mercury) which is the measurement used on a typical vacuum gauge. 3-6" of H2O is not very much. The goal of the CCV as others have stated is to maintain a slight vacuum under all conditions.
Your flow directions are correct except for the vacuum hose. The RealOEM parts diagram is INCORRECT. There is NO vacuum hose. When you remove your old CCV, you will see that the vacuum hose connector is capped and the new replacement CCV is also capped.
Based on Fudman's comments, I searched for RDL's comments and found where he also confirmed his 530i also does not have the orange-striped vacuum line that Aioros has on his 99 528i.
- CCV replacement tips
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)?
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.
Great explanation, RDL! In plain understandable English, too. The best description of CCV function and malfunction I have seen to date. #5 also explains why BMW enlarged CCV return on the dipstick tube. Thanx. :thumbup: :thumbup:
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.
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.
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.
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.
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.
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?
I have an M54 so I'm not really familiar with your engine. I have though seen the pictures and diagrams of the air hose off the CCV running to the fuel pressure regulator.
When I first saw those pictures a couple of years ago, I was baffled at the design intent. I finally realized that "operated with crankcase vacuum" is technically accurate. But assuming the CCV is working properly it is really so close to atmospheric pressure that it makes no practical difference. The CCV regulates crankcase vacuum to less than 15 millibar, or EDIT 1.5% (not 0.15% in original post) different from atmospheric pressure.
I think the purpose of taking a reference pressure this way is to provide clean, filtered source of atmospheric pressure to the fuel pressure regulator without any chance of engine bay dirt, grit and grime fouling the sensitive parts of the small fuel pressure regulator. By comparision, the CCV is about 3 inches in diameter & much less sensitive to dirt. An awkward, klugey way to achieve the result in my opinion.
For the M54, BMW changed the design to take atmospheric reference pressure from the F fitting in the boot between the MAF and inlet manifold. That supply is kept clean by the engine air cleaner.
I typed /m52 ccv F3 in the bestlinks and it came up with this thread which covers that issue in exquisite detail:
- Sorely needed clarification on how the M54 CCV vacuum port works on the M52 CCV valve connection to the fuel pressure regulator connection (1)
I think the purpose of taking a reference pressure this way is to provide clean, filtered source of atmospheric pressure to the fuel pressure regulator
EDIT:
I tried to test the CCV system by checking manifold vacuum, as shown here - but I think I failed to conclude much of anything:
- How to test the crankcase ventilation pressure regulating valve system (1)
Two years ago, my car failed vacuum at 9 inches but had no symptoms at all: engine performance & idle qualtity were normal, no DTCs were present and no smoke from the tailpipe. A couple of months later the CCV system failed entirely. The engine then refused to idle, generated a raft of DTCs and lit up the CEL. Even after failure, I had no smoke. However, while replacing the entire CCV system I discovered a hole in the drain hose to the sump which created a large vacuum leak. The CCV valve body may have been functioning well enough to avoid driveability symptoms if the drain hose hadn't failed.
The 8 inch vacuum by your engine is a failure vs the specs of 4 - 6 inches. I conclude your CCV is failing but not so badly as to generate driveability symptoms. FWIW, if this were my car I'd continue to drive it but check vacuum regularly and have new CCV parts on hand. My logic being that although out of spec, the 8 inches of vacuum is still so weak that it is very unlikely to generate any other problems. And I don't know what I'd consider too much vacuum to tolerate; probably 12 inches (2 times upper spec) but that is an absolute double X triple WAG - not a SWAG since there is no science behind it. Or maybe I'd just wait for a nice day, replace the darn thing and be done with it.
I've never been able to understand the physics behind the blow for bubbles test. And I never got bubbling: not with 9 inches vacuum, not after my CCV failed entirely (but then it wouldn't with a hole in the drain hose) and not after CCV replacement with vacuum in spec.
Consider that with the vent hose disconnected from the valve cover and blowing into it, the chamber in the CCV is at atmospheric pressure or slightly above; certainly no vacuum. Therefore the CCV's diaphram and orifice will be wide open, ready to draw vacuum on the vent hose (and thus crankcase, if connected) as soon as the engine is started and inlet manifold vacuum is present. The air being blown into the vent hose will take the easy route to the inlet manifold rather than the path down into the sump to make bubbles. It seems to me that the only way to get bubbling would be for the diaphram to be failed closed or the distribution piece on the manifold to be clogged. In this case one would have +ve pressure with the engine running - a definite CCV failure. Yet a pass for a good CCV is supposed to be a little resistance and bubbling when blowing into the vent hose.
Interesting. Where did you check the vacuum from? I placed my clear hose over the dipstick.
I have been meaning to doublecheck mine again just to make sure I didn't do it incorrectly so if there are other places to doublecheck the vacuum, that would be useful as a check of my procedure.
I understand that logic. That's what I did with my cooling system. The CCV, even for you guys, is a pain. So just imagine how time consuming it will be for me!
Me neither. I don't personally think it tests anything. I said so in the aforementioned CCV test thread but I'll append your deduction also so as to add weight to the premise.
I never thought of it as a reference to atmospheric pressure. I've assumed that it was necessary too let the volume behind the diaphragm vary without restriction.
As I recall, in one type of FPR the return flow is blocked under low vacuum, such as acceleration. Another type of FPR actually increases return flow under high vacuum situations like idling. I suppose one could design a FPR to do both, but I've assumed that the FPR on the e39s are the second type that lower fuel rail pressure during high vacuum.
If I understand what you've written, you think that the FPRs on the e39s don't really use a vacuum source to move the diaphragm, only to vent area behind the diaphragm. Certainly the M54 FPR will not see a strong vacuum since it's connected upstream of the throttle. Assuming that the CCV is operating at crankcase vacuum, it would be insignificant for the M52, too.
As I recall, in one type of FPR the return flow is blocked under low vacuum, such as acceleration. Another type of FPR actually increases return flow under high vacuum situations like idling. I suppose one could design a FPR to do both, but I've assumed that the FPR on the e39s are the second type that lower fuel rail pressure during high vacuum.
If I understand what you've written, you think that the FPRs on the e39s don't really use a vacuum source to move the diaphragm, only to vent area behind the diaphragm. Certainly the M54 FPR will not see a strong vacuum since it's connected upstream of the throttle. Assuming that the CCV is operating at crankcase vacuum, it would be insignificant for the M52, too.
A simple FPR will do both automatically, it wouldn't need two different types or a special, complex design. In both the cases you describe injector pressure changes in the same direction as the change in reference (manifold) pressure. This is normal response for a pressure regulator. You can work through the steps by considering vacuum to be -ve pressure and that blocking return increases injector pressure, increasing return flow reduces injector pressure.
I should clarify that vacuum doesn't move the diaphragm and the hose isn't simply a vent. Rather the balance of force from reference pressure on one side, force from fuel pressure on the other side, plus spring force determines the output pressure. The purpose of the air hose to FPR is to provide the reference pressure that the engine designer planned.
TIS describes that the M52 does change fuel pressure under different engine load conditions (high load / acceleration = low manifold vacuum, low load / idle = high vacuum) and apparently uses varying vacuum to the FPR to do so. However as I mentioned in the earlier post, I just can't work out how the tap off the CCV provides that changing vacuum to the FPR.
TIS does not say anything about the M54 varying fuel pressure with load.
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
BimmerFest BMW Forum
11.4M posts
753.1K members
Since 2001
A forum community dedicated to BMW owners and enthusiasts. Come join the discussion about Bimmerfest events, production numbers, programming, performance, modifications, classifieds, troubleshooting, maintenance, and more! Bringing the BMW community together.