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Thread: CCV and Dipstick

  1. #1
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    CCV and Dipstick

    Happy Holidays, all.

    I'm trying to diagnose my oil consumption, and I've narrowed it down to worn oil rings and a lack of enough vacuum in the crankcase - typical. I'm intending to try the 02Pilot vacuum hose mod, but I haven't done any repairs yet because I want to get the oil level down to spec (see below) and then see how long it takes to go through a quart.

    But an odd thing has me puzzled. After regular drives and then letting the engine cool down, I check the dipstick and the oil level shows way above the plastic guide/gauge, up the metal rod an inch or so, even 24 hours after it's been driven. I wipe it clean off, put the dipstick back in and my oil level then shows just 1/8" above the FULL notch, barely onto the upper plastic block on the stick. I didn't know if the CCV oil return hose had anything to do with that, but I just read that the M54 can suck oil up out of the dipstick tube if the CCV isn't working properly. Is this odd oil reading a symptom of this? If this is happening, there has to be enough vacuum in the CCV and hose to hold that oil in the dipstick tube long after being driven. Or perhaps when I pull the dipstick out, it's releasing vacuum pressure and oil quickly drains out of the CCV onto the dipstick...? Crazy...

    Some history: bought the car five months ago, '02 325iT, 162K on the original engine. PO stated he thought there was an oil leak (likely the pan gasket) but I have yet to see any sign of a leak. Changed the oil after purchase (along with VC gaskets, coolant and many other things), everything seemed fine. Then 1000 miles or so later I get the low oil level light and the dipstick showed dry - which freaked me out. I topped off the oil (waaaaay too much, probably two quarts too much, because the added oil wasn't reading on the dipstick) until I got a full reading. Having too much oil didn't seem to harm anything and the level slowly (over another 1000 miles) reduced to where the oil level is consistently where it's supposed to be, and I've been keeping close track of it because I want to know how quickly the engine is going through the oil. But now that the level is as I stated above, just barely over full, no oil consumption at all in at least two tanks of gas. Nothing odd except the aforementioned oil in the dipstick tube.

    I live in a warm climate (SoCal) so cold weather isn't a factor. Do these symptoms sound familiar to any of you?

  2. #2
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    The proper way to check engine oil level:
    Engine off-Pull dipstick-Wipe clean-Reinsert for several seconds-Pull dipstick-Examine oil level.
    Check levels regularly, if oil consumption continues replace CCV System(Valve + all associated hoses) before attempting modifications.

  3. #3
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    Yes, the M54 engine can suck oil up through the dipstick tube. Has the CCV ever been changed? That’s the likely culprit. With the engine running remove the oil fill cap. Check the oil fill hole for vacuum. There should be a slight vacuum present.

  4. #4
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    Yes, the oil level was checked properly with the engine off, and long after being driven. If I had just shut off the engine and checked the dipstick, it would make sense that the entire stick would be coated in oil. I just don't understand why there would still be residual oil so far up the dipstick long after the engine is turned off and cooled down. Virtually every other car I've owned (including 12 BMWs) have shown accurate oil levels after all of the oil has drained back into the pan, including off of the stick.

    Marco, I doubt the CCV has been changed. I'll do the vacuum test and get back to you.

  5. #5
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    Update:
    After a thorough 3-hour drive this afternoon, still zero oil consumption, same situation with oil up the stick after sitting for two hours after the drive; very wet, not just residual oil.

    Marco,
    I have no vacuum at the dipstick tube at idle, but I do have minor vacuum at the oil fill in the VC. Interesting thing, I could clearly hear some low "gurgling" from the dipstick tube when I pulled out the stick, which also quieted when I re-inserted it. Sound is definitely coming from the dipstick tube. I figure this means the CCV is trying to suck oil up its hose, yes?

    Thanks, guys.

  6. #6
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    You still must wipe it clean beforehand to get an accurate reading.
    If the CCV system has never been replaced by PO, at your mileage it's probably best to replace now.

  7. #7
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    Okay, maybe I wasn't being clear: I know how to properly check the oil level - that's not my concern, since my oil consumption/loss seems to have stopped. My question is *why* the oil shows so high up the dipstick long after I've turned the engine off. In 24 hours of non-running, any residual oil on the dipstick should have drained off of the stick into the pan. It would also leave an oil residue behind (hence why we wipe the stick to get an accurate reading) but as I said above, this is particularly wet, not just a film of oil; it's almost dripping off the top of the gauge, which doesn't submerge into the pan oil so no reason it should be that wet. I can see how oil is supposed to drain out of the CCV and into the dipstick tube and would run down the dipstick (when working properly) while the car is running, and shortly thereafter. But 24-36 hours later, the entire yellow plastic measuring gauge is still well-coated with oil - including the 4 "petals" at the top - and about 1" up the metal rod. Yes, I wipe all of that off and re-dip the stick, which then shows the correct oil level. My point is, it seems that oil is staying in the tube and not draining into the pan after being driven, like plugging the tip of a drinking straw to hold Coke in it. And if so, when I pull the dipstick out, that oil seems to be released to drain down to the pan. Maybe this is absolutely normal for the M54 engine family. But if the CCV is sucking - and holding - oil in the dipstick tube, that would explain what I'm finding. OR, if the CCV is working properly, and this much wet oil on the dipstick is normal, then I don't want to get into replacing the CCV if I don't have to.

    I know you're trying to help, MIKYZZ4, but let's assume I've been working on cars all my life, including full restorations, engine and transmission rebuilds. I still appreciate your input. Thanks again.

  8. #8
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    Sorry-my mistake,
    I will defer to Marco, so I will not have to repeat what he has already posted,
    but I do agree, a failed CCV is the likely culprit of excessive oil consumption.

  9. #9
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    I think the CCV body (the part to which the hoses attach) is bad. The dipstick shouldn’t have oil on it much passed the plastic level inductive. It sounds like the CCV body is occasionally trying to suck oil out of the crankcase. This can lead to a hydrolocked engine. A hydrolocked engine is typically toast as the connecting rods are usually damaged. I’d replace the entire CCV system ASAP. Btw, the M54 CCV was designed by an engineer who’d been fired by Audi. True story.

  10. #10
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    the oil dipstick tube has a separate compartment to drain the CCV. the oil from the ccv is probably draining onto the dipstick and indicating an over full condition until you wipe off the stick and re-check it..... I would guess that your CCV is failed.....

  11. #11
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    Thanks for the replies, guys. I figured the CCV was bad (or failing) at this mileage. The weird thing was the oil consumption and then being filled and not reading on the stick, and then... no oil consumption. So something changed when I (over-)added the oil. The CCV's a dirty job, but somebody has to do it.

  12. #12
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    CCV Update

    UPDATE

    So I bit the bullet and got the CCV replacement kit, hoses, etc., as well as the two large rubber intake elbows. I did the replacement without removing the intake, based on The 50's Kid video, and it worked out well. With the dipstick tube removed, I checked for flow in both the main tube as well as the CCV drain/return tube - all was good. I also added a vacuum line from the CCV to the rear of the intake, as suggested by 02 Pilot. The only setback was after re-assembly, I wasn't getting a reading from the throttle body. Crap! I knew that I had plugged it back it... Took off the surrounding parts and found that the plug was on, but not on far/deep enough. Pushed in on harder, put it all back together, and code was gone

    And the verdict? Looks like problem solved. After a short drive to get the oil flowing, I turned it off and checked the dipstick; oil was up to the full mark but nothing above that. I probably did have oil being sucked up the dipstick tube from a bad CCV valve. Dodged a bullet by replacing everything. And what I removed was probably OEM from the factory - everything was brittle, and broke apart while I pulled on it.

    Thanks again for the tips and insight, guys.

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