How to test the BMW E39 pressure-controlled crankcase ventilation system (CCV)?

Originally Posted by Jason5driver

Blue-B,
You should not have a lot of vacuum coming from the dipstick tube.

The cellophane test doesn't provide enough granularity ...


But I think we came up with a good (i.e., simple) test for when the bottom of the dipstick guide tube is clogged!
- How to test, clean, & redesign the original BMW dipstick guide tube (CCV vent clogs!)

The simple suggestion is to elevate the vehicle and temporarily disconnect the rubber lower CCV vent hose, and then insert a test hose onto the steel CCV vent finger of the dipstick guide tube.

Blowing on 'that' test hose should instantly indicate whether or not the dipstick guide tube is clogged.

BTW, I measured my original CCV vent hose at 0.430 inches inside diameter (ID) ... which is about 11 mm metric, or about 7/16 inch SAE ID.

Originally Posted by Jason5driver

Blue-B,
You should not have a lot of vacuum coming from the dipstick tube.

Fixed...^^^

When i remove the dipstick to check the oil level, it's very hard to pull out. Clean it, re-insert to accurately measure the oil level, comes out easy. this is clockwork. So, the vacuum is pretty strong?
Another weird thing:
Before changing the CCV (& new style dipstick) to the winterized version I always knew exactly my oil level.
With the new dipstick, it's very iffy. Example: change the oil (as always), re-fill 7 qts, check oil, the oil level should be at max. Wrong. It barely shows at the bottom, BELOW the first notch of the min level. Drive it for a day, the oil level is at max - upper notch level. Drive it one more day, the level is at the middle. Check it every other day or so, every time the level is different (pending on the car's mood?) between the lower notch and the max notch. My garage floor level never changes.
What gives? This started to happen right after the CCV was changed to the "new" winterized version.
That CCV system and whoever designed it should be shot Together with the one who designed the SAP.
I hope Gary comes up with an update for the CCV very soon

Doru,

You might try opening the oil filler cap before checking the oil level. Just in case residual vacuum plays any part in the inconsistent oil level.

Steve

Originally Posted by doru

the vacuum is pretty strong?

I'll say! I measured just under 8 inches of water over in this thread yesterday (engine idling for about five minutes, everything connected except the dipstick itself).
- How to test, clean, & redesign the original BMW dipstick guide tube (CCV vent clogs!)

The whole point is to come up with a test of the CCV system and the oil dipstick guide tube portion too. So I was following RDLs advice ... but ... maybe I did something wrong measuring my oil dipstick guide tube vacuum ... because 8 inches is a whopping 19 milliBar (which is a tad too much vacuum given the BMW spec of 10-15 mBar).

Maybe I made my loop too loose (does the loop size matter?) or maybe, since it was a cold idle of about five minutes or so, maybe the 'cold idle' gave me "too much vacuum". I don't know. I don't even know HOW to reduce vacuum, if it indeed is too high.

Let's bear in mind what we're looking for is a TEST for the CCV system and dipstick - so - it would be nice if someone else can run the almost-free water manometer test that RDL suggested earlier.

Here's what I had posted yesterday - but no response yet:

Originally Posted by bluebee

#1: I bought 7 feet of 3/4" OD x 5/8" ID vinyl hose.

#2: I slipped one end over the oil dipstick guide tube.

#3: Making a loop, I filled it with about a foot and a half of water.
Note: Less water bounced around too much when the engine was at idle so I added more until it stabilized, yet didn't go into the engine.

#4: Starting the engine, I roughly measured the water delta to be just under 8 inches (it would have been easier had I a helper).
EDIT: I'm going to try again, but with a helper, and more string to keep things more vertical and parallel.

Here's a picture of the final setup in my carpeted garage last night.


So, may I ask:
Q: What does 8 inches of water at relatively cold idle tell me about the condition of the engine?

Originally Posted by doru

When i remove the dipstick to check the oil level, it's very hard to pull out. Clean it, re-insert to accurately measure the oil level, comes out easy. this is clockwork. So, the vacuum is pretty strong?
Another weird thing:
Before changing the CCV (& new style dipstick) to the winterized version I always knew exactly my oil level.
With the new dipstick, it's very iffy.

... stuff deleted ...

That CCV system and whoever designed it should be shot
... stuff deleted ...

Doru

I have the new, cold weather guidetube too & have found oil level measurements to be consistent. Perhaps the retaining brace and bolt for the tube on your engine is a little loose. If the guidetube can move up & down even slightly, the dipstick reading will be thrown off. The span from lower to upper mark on the dipstick is only 16mm or 5/8" so it wouldn't take much movement in the guidetube to make a difference between a reading of full and down half a quart/litre. I can't think of another reason for the inconsistent results you are seeing.

BTW, my dipstick is sticky too. It was on the old concentric tube design & still is with the new cold weather version. But it isn't vacuum. A properly functioning CCV will hold crankcase vacuum at 4 - 6" w.c. which converts to ~0.25 psi. Guide tube diameter is ~1/2" for an area of 0.2 sq. in. So the force exerted by the vacuum is ~0.05 lb or ~3/4 ounce. Besides, once the engine stops crankcase vacuum bleeds away in seconds; long before I'm under the hood yanking on the dipstick. The stickiness must be caused by the O-rings adhering to the guidetube.

I do agree with you the BMW's CCV compares badly with the PCV I'm used to with its $15 cost & 5 minutes to change. It calls to mind advice a mentor gave me years ago: "there comes a time in every project when you have to shoot the engineers and get on with it." I think BMW missed that checkpoint on this engine.

Originally Posted by rdl

the BMW's CCV compares badly with the PCV

Agreed.

But, at least we can come up with some simple (almost free) tests to determine if the tear-down is necessary or not.

So far, does this summarize the three simple CCV tests?
(If so, may I ask others if they get similar readings because my results were iffy ... or ... my results might actually indicate a leaky CCV diaphragm.)

DIPSTICK GUIDE TUBE VACUUM:
1. Using a 5/8" ID rubber tube about three feet long, my M54 vacuum at idle at the dipstick guide tube was just under 8 inches of water. It would be nice to see what others get using a hose and water and some string and a ruler. Note: I will run the test again, taking more care to keep the water-filled parallel lines vertical.

UPPER VENT PIPE RESISTANCE:
2. Using a 1/2 inch OD rubber hose about seven feet long (with some tape wrapped around the end for tight fit), I felt absolutely NO RESISTANCE to blowing into the CCV upper vent tube whether the engine was running or not - and - whether the engine was at idle, low speed, or high speed (it's hard to tell the speed because I had to prop the accelerator with a heavy object).


This might be indicative of a torn CCV diaphragm according to Steve's post just now in the related thread:

Originally Posted by Steve530

The CCV regulating valve controls the intake manifold vacuum applied to the crankcase, so a higher than normal vacuum in the crankcase would mean that the regulating valve is allowing too much vacuum to be applied to the crankcase. That might be caused by a diaphragm that is not closing off the vacuum port to the intake manifold hoses.

LOWER VENT HOSE RESISTANCE:
3. Using a 7/16 inch ID hose (11mm ID) about three feet long, from under the car, one can temporarily disconnect the rubber ccv vent hose and connect a three foot rubber hose to the bottom finger of the steel dipstick guide tube and blow to see if the concentric ring is clogged. In my case, I unclogged that already - but it would be nice to see what others get when they test it.

Originally Posted by bluebee

... stuff deleted ...
DIPSTICK GUIDE TUBE VACUUM:
... stuff deleted ...
Note: I will run the test again, taking more care to keep the water-filled parallel lines vertical.

UPPER VENT PIPE RESISTANCE:
... stuff deleted ...
I felt absolutely NO RESISTANCE to blowing into the CCV upper vent tube whether the
... stuff deleted ...

Bluebee
There is no need to keep the lines vertical, parallel, any particular shape or anything else. The only thing that matters is the vertical distance between the two water levels. Keeping the two legs of the "U" vertical & together does make it easier to measure though.
I'm afraid that the reading of 8" you got indicates that the CCV is suspect, assuming they were vertical inches.

I appreciate that the "blow for bubbles test" has been recommended for some time. It has never made sense to me. (Doesn't work for me either) Making bubbles would require pressurizing the CCV chambers in order to force air down to the dipstick guidetube and bubble through the oil in the sump.
But, while the engine is operating the CCV is keeping the port to the inlet manifold open "just the right amount" so that the hose (which the CCV thinks should be connected to the crankcase) has 4 - 6" w.c. vacuum. Any pressure rise generated by blowing into the pipe would cause the CCV diaphram to open the port wider to overcome the effect and maintain vacuum.
When the engine is stopped, the CCV default position is for the port to inlet manifold to be fully open; again impossible to generate pressure to bubble through the oil. Any pressure would go to the inlet manifold, past the throttle toward the engine air filter, or though a cylinder that has both valve open in overlap and down the exhaust.

Can anyone report that they have succeeded in making bubbles with a properly functioning CCV?
If so, please disregard my theory above.

Originally Posted by Steve530

I suggested removing the DISA so you can look for signs of oil inside the intake manifold. One failure mode of the CCV causes oil to be sucked into the intake manifold. You really should try the trick described on page 1 of this thread as RDL suggested. That's the easiest way to get some idea if the CCV is working. It only takes a few seconds.

There is another simple test where you remove the oil filler cap and replace it without tightening it. With the engine running, you should feel some resistance when you once again try to remove the cap. If the cap is difficult to remove or is not held by vacuum, then the CCV is suspect. The problem with this test is that it is subjective, not objective like the plastic bag test.

The ICV is the device that the smaller branch of the lower intake air boot attaches to. It's used to allow air to bypass the throttle plate. I'm not sure if your car has an idle control valve, but if it does, it's a good idea to clean it if you can easily get to it while doing other maintenance. There are lots of good DIYs around about cleaning the ICV.

Interesting...
Because I specifically remember finding sandy oil inside the intake manifold after removing the Disa Valve...
So, if there is oil in the Intake manifold, the CCV is most definitely DEAD...?

Thanks!
Jason

Originally Posted by Jason5driver

Interesting...
Because I specifically remember finding sandy oil inside the intake manifold after removing the Disa Valve...
So, if there is oil in the Intake manifold, the CCV is most definitely DEAD...?

Thanks!
Jason

I don't concur.
The separator will work only so good. Some misted fumes are still pulled through the intake manifold. So wether the CCV is new or old, it will always have some oil in there.
If the CCV is blown, the amount of oil may be higher than normal.
Because if that's the case, a CCV will last probably only 2-3 months. My DISA was oily after the new CCV went in - checked it about 4-5 months later.

Originally Posted by Jason5driver

Interesting...
Because I specifically remember finding sandy oil inside the intake manifold after removing the Disa Valve...
So, if there is oil in the Intake manifold, the CCV is most definitely DEAD...?

Thanks!
Jason

No, I don't think that if you find a little oil in the intake manifold that it always means that the CCV has died. I suspect that Doru is correct that there may be some oily residue even if the CCV is working well.

In that specific post I was trying to warn the person that a failed CCV can suck oil into the intake manifold. So if you have no leaks, but the oil level is dropping, it's worth checking that there isn't lots of oil being sucked into the manifold by a failed CCV. There was a post in another thread about an engine that was hydrolocked by oil that was sucked into the cylinder through a failed CCV.

I guess I did a poor job explaining that issue. Sorry if it caused confusion.

Originally Posted by Steve530

No, I don't think that if you find a little oil in the intake manifold that it always means that the CCV has died. I suspect that Doru is correct that there may be some oily residue even if the CCV is working well.

In that specific post I was trying to warn the person that a failed CCV can suck oil into the intake manifold. So if you have no leaks, but the oil level is dropping, it's worth checking that there isn't lots of oil being sucked into the manifold by a failed CCV. There was a post in another thread about an engine that was hydrolocked by oil that was sucked into the cylinder through a failed CCV.

I guess I did a poor job explaining that issue. Sorry if it caused confusion.

Roger that...!
Thank you for the response, and I very much respect your posts...!
Very informative...!
Thank you!

Jason

I found a great read here:
http://www.aa1car.com/library/pcv.htm


And, a possible CCV alternative (Crawford AOS "Air/ Oil Separator"):
http://www.iwsti.com/forums/2-5-lite...-answered.html

http://store.crawfordperformance.com.../categories/78

Review:
http://forums.nasioc.com/forums/show....php?t=2228499

And a related thread by BimmerFiver about the Leak Detection Pump at the Charcoal Canister (Fuel Tank):
http://forums.bimmerforums.com/forum...1#post24609271

Originally Posted by AA1car

If the pintle inside the PCV valve sticks open, or the spring breaks, the PCV valve may flow too much air and lean out the idle mixture.
This may cause a rough idle, hard starting and/or lean misfire (which increases emissions and wastes fuel).
The same thing can happen if the hose that connects the valve to the throttle body, carburetor or intake manifold pulls loose, cracks, or leaks.
A loose or leaky hose allows "un-metered" air to enter the engine and upset the fuel mixture, especially at idle where the idle mixture is most sensitive to vacuum leaks.
On late model vehicles with computer engine controls, the engine management system will detect any changes in the air/fuel mixture and compensate by increasing or decreasing short term and long term fuel trim (STFT and LTFT).
Small corrections cause no problems, but large corrections (more than 10 to 15 points negative or positive) will typically set a lean or rich DTC and turn on the MIL.

And, the fuel trims were also mentioned by that retired BMW tech. I met at Starbucks a couple Saturday's ago, when he used his code reader on my car...
He highly suggested running a WHOLE CAN of B12 carb/ throttle body cleaner through the intake/ throttle body while running my car to FIX ALL of the issues with my car (leaking oil pan gasket, fuel pump acting-up, CCV dying again...)...

For the record, here is an E46 with the lower CCV vent hose sliced almost exactly as mine was (with concomitant lean-condition misfire error codes):
> CCV valve and vaccum leak diagnotics

Originally Posted by carl0s

I have been trying to track down vac leaks on my e46 330i for a few weeks now. I already replaced the valve cover gasket, oil filter housing gasket and both intake boots. All of which were badly perished.

Up until today, I was seeing +28 at idle on the short term fuel trims (but 0 on the long terms.. this confused me, but you say that's expected..). This was triggering the "system too lean" codes.
Thanks to a post on another forum, I discovered that the lower oil separator -> dipstick hose was fractured ( see http://forum.e46fanatics.com/showthread.php?t=773551 ). Mine looked like this:

After replacing this hose today, I am now seeing short term fuel trims hovering around 11 - 14% at idle.

More details here:
- P1188, P1189, etc Codes Fixed Easily (1 Oil Separator Hose) (*Pics*)

Originally Posted by bluebee

Agreed.

But, at least we can come up with some simple (almost free) tests to determine if the tear-down is necessary or not.

So far, does this summarize the three simple CCV tests?
(If so, may I ask others if they get similar readings because my results were iffy ... or ... my results might actually indicate a leaky CCV diaphragm.)

DIPSTICK GUIDE TUBE VACUUM:
1. Using a 5/8" ID rubber tube about three feet long, my M54 vacuum at idle at the dipstick guide tube was just under 8 inches of water. It would be nice to see what others get using a hose and water and some string and a ruler. Note: I will run the test again, taking more care to keep the water-filled parallel lines vertical.

UPPER VENT PIPE RESISTANCE:
2. Using a 1/2 inch OD rubber hose about seven feet long (with some tape wrapped around the end for tight fit), I felt absolutely NO RESISTANCE to blowing into the CCV upper vent tube whether the engine was running or not - and - whether the engine was at idle, low speed, or high speed (it's hard to tell the speed because I had to prop the accelerator with a heavy object).


This might be indicative of a torn CCV diaphragm according to Steve's post just now in the related thread:


LOWER VENT HOSE RESISTANCE:
3. Using a 7/16 inch ID hose (11mm ID) about three feet long, from under the car, one can temporarily disconnect the rubber ccv vent hose and connect a three foot rubber hose to the bottom finger of the steel dipstick guide tube and blow to see if the concentric ring is clogged. In my case, I unclogged that already - but it would be nice to see what others get when they test it.

After seeing this old thread revisited and updated, here's a suggestion directed mainly at the older forum members who do most of this troubleshooting on our cars (and thank you for your efforts! ). When we propose a test to determine the condition of a system or component, we should clearly define the pass/fail or go/no-go criteria associated with the test. I know it's mentioned in earlier posts within this thread but that would require reading this entire thread, which some won't do. While reading the entire thread is very educational, I am guessing that many of the newbies simply want the answer ASAP. This is just to make things as simple as possible for the lowest common denominator.

I've read some other threads about the oil seperator hose going bad. It looks like on the V8 you have to remove lower cover/jesus bolt to do so, but perhaps people could have some success just replacing a hose if you remove one upper timing cover (much easier). I'm considering this right now, but I've only read of one person replacing a hose in their oil seperator. The pipe that runs to my oil seperator had a lot of gunk on the end near the oil seperator and a bunch of gunk was in the valley pan area. Makes me worry about the oil separator.

This useful distinction was posted to this thread today:
> E39 (1997 - 2003) > How to test, clean, & redesign the original BMW dipstick guide tube (CCV vent clogs!)

Originally Posted by bluebee

In a post today, someone with a blinking SES and three cylinders out reported that the shop is intimating a clogged CCV caused the problem, as evidenced by oil in the intake:
- SES light

My question (keeping in mind Fudman's initial response to a similar question in post #8 of this thread & a more detailed response in post #19):
Q: Could a clogged CCV or dipstick tube really cause 3 cylinders to misfire consistently?

Originally Posted by doru

Not on the v8. the dipstick goes straight into the sump without any other "attachments" (read tubes).



V8 CCV design is actually a cyclone, a different design than i6. It has no diaphragm.



The vacuum is created different.



Also, if ingestion occurs, the cylinder bank that gets it should be all disabled, not only 3 cylinders. Why is the 4th healthy?

Hello. In my M52 is little vacuum under oil cap, and in dipstick. Maybe it is ok, but what I'm worry about is very low vacuum on hose connecting fuel presure regulator with CVV. Engine is working little rough. Hoses seems to be fine (only hose I didn't checked is CVV hose connected with oil dipstick, but I will do it soon), without vacuum leak, valve cover gasket also good, new, checked with auto-start fluid, CVV is new. But why is so slightly vacuum on hose connected to fuel presure reguletor? Almost no vacuum at all... Is this correct? FPR can operate with so slightly vacuum?

Originally Posted by Zakov

Hello. In my M52 is little vacuum under oil cap, and in dipstick. Maybe it is ok, but what I'm worry about is very low vacuum on hose connecting fuel presure regulator with CVV. Engine is working little rough. Hoses seems to be fine, without vacuum leak, valve cover gasket also good, new, checked with auto-start fluid, CVV is new. But why is so slightly vacuum on hose connected to fuel presure reguletor? Almost no vacuum at all... Is this correct? FPR can operate with so slightly vacuum?

Atmospheric pressure or alternatively the very weak vacuum that you mention is what the fuel pressure regulator needs to operate correctly.

The fuel pressure regulator needs a good clean source of atmospheric pressure to function correctly. See this thread,
http://www.bimmerfest.com/forums/sho...=1#post7145659
post #41 for one possible explanation of the air hose from CCV to regulator.

Thank you very much!

Originally Posted by rdl

See this thread

For the record, in that thread, the related information below was posted today about the bubble test:

Originally Posted by rdl

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.

For M52 vs M54 operation of the CCV vacuum port, see this thread:
> E39 (1997 - 2003) > WHERE does the CCV vacuum source port go for the E39 CCV valves that are not plugged?

From reading this E46 thread today, I just belatedly realized what the BMW design flaw is in the lower CCV vent hose!
> E46 (1999 - 2006) > What is this sensor / plug /wire near the intake?

Is it correct that the 90° elbow on the original CCV lower vent hose puts so much stress on the hose that they often crack in half?

And, is the replacement 45° hose designed to put less stress at that point?

This thread today covers how to temporarily disable the CCV to limp home in dire cases:

Originally Posted by vandyboy

I did a quick google check on driving with a failed CCV. I saw a thread on E46 Fanatics that said some of the potential problems are hydrolocked cylinders and damaged seals. They did not state how long it takes for those things to occur.

Since it appears this the CCV just failed, I think you should be okay if you drive it easy back to your place, with a full compliment of extra oil on hand.

Found this posted today, which is something to look out for BEFORE installing a new CCV I guess...

Originally Posted by JasonSC540ia

I just replaced my CCV for preventive maintenance. After I replaced it with one of those $40 ones it had the symtoms of a failed CCV (howling, extreme suction sound when dipstick pulled). I replaced just the back cover and diaphragm with another one. Failed CCV symtoms gone. Further inspection reviled this, one the "new" CCV diaphragm.



If you bought a non OEM one and your still showing signs of failed CCV, might be something to look at.

EDIT: And this was posted soon thereafter:
> E39 (1997 - 2003) > Testing ccv

I think we have two good threads for testing the CCV:
> E39 (1997 - 2003) > Cute little trick to diagnose blocked CCV system...
> E39 (1997 - 2003) > How to test the BMW E39 pressure-controlled crankcase ventilation system (CCV)?

So, I'm not sure which should be the canonical thread to cross-reference this information posted today (in order for others to find it more easily in the future, long after we're gone).

Originally Posted by THEHULK

Just checked crankcase pressure from both the dip stick and the oil fill. Both readings about -6"wc with a warm engine.

Originally Posted by THEHULK

...my CCV was bad. I just replaced and had a big rip in the diaphragm. Tested the new one with a manometer and has reading moving around from 3 to 6" WC.... I highly recommend the use of a manometer to test.