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Thread: Venting the M54 Crankcase to the Atmosphere

  1. #1
    Join Date
    Feb 2018
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    Venting the M54 Crankcase to the Atmosphere

    Let me start by saying I've read a ton of posts on M54 oil consumption and having built a couple engines so I am familiar with the concept of piston rings.

    My newly acquired 2005 X3 with a 2.5L M54 was guzzling a quart of oil every 150 miles. That's right. I got ripped off. Oh well. No white smoke from the exhaust. None. No leaks or drips. Not even a drop. It's a new-to-me vehicle with 100K miles that may have been neglected. As a way of troubleshooting I completely bypassed the CCV. Blocked everything off and vented the crankcase to the atmosphere. With no crankcase vacuum a fair amount of white smoke now whisps from the crankcase vent port. Engine still uses the exact same amount of oil. One quart every 150 miles. I have two explanations for this: 1. CCV was fine but I have worn or coked oil control rings; 2. By some strange coincidence the amount of oil an M54 without crankcase vacuum consumes is the same as that of one with a bad CCV.

    After bypassing the CCV and not getting the results I had hoped for I read a ton more posts. I then suspected that I could have coked oil control rings but still good compression. That's a valid condition on these engines, right? Well I tried Marvel Mystery Oil and Seafoam treatment in the crankcase to no avail. After two quarts of Marvel and two oil changes and two quarts of Seafoam and two more oil changes consumption is the same.

    Thoughts? Is there a logical next step to diagnose before throwing in the towel and assuming the oil control rings are toast? Compression test? Engine is peppy and like I said no smoke out the back.

    As an owner of a 2004 E46 325 I granted myself permission to post in the this forum for this issue instead of the X3 forum thinking I'd get a better answer here.

    Thanks for your help.

  2. #2
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    The M54 crankcase needs to be under a vacuum or else it’ll burn oil. That’s what the CCV is supposed to provide-vacuum. The CCV was designed by an engineer fired by Audi (imho)! So, bite the bullet and install a new OEM CCV. See if that reduces the oil consumption. If it doesn’t, your next step is to buy GM Top End cleaner from amazon. Then go to E46Fanatics and search for threads on the top end soaking process. If the engine still burns oil you can install an oil catch can. The can will provide even vacuum.

    Also double check for lesks at the oil filter housing. The M54 is notorious for leaking there. A new gasket is less than $10.

  3. #3
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    Pardon my intrusion but I saw this under the new posts and had to look. I had a Lexus RX 300 develop the same kind of oil consumption around 200k miles (no history of abuse) from coked up rings. I was able to get them free by soaking with seafoam straight in the cylinders. It will work best to lift the passenger side up to help bring the block a little closer to level. Drain the oil out and leave the plug out of the pan so you can see how quickly the detergent is flowing past each cylinder, a compression test beforehand will certainly identify the worst. Manually work the crank shaft back and forth to help free up the rings and keep adding seafoam until the the rings can slow down the flow. I let it sit overnight and cranked it over in the morning with the plugs out and rags to catch the spray. I didn't think to pull my O2 sensors but they were fine. This is a pretty aggressive treatment and it may dislodge big chunks of carbon that could cause other problems but I looked at it from the pespective that the engine is basically done and it was worth the risk. My compression returned to within spec and I kept at it with the crankcase treatments like you have already done and I got another 70k miles out of the car till I sold it.

  4. #4
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    The pros over at E46Fanatics use GM Top End cleaner. It’s very strong stuff.

    https://www.amazon.com/Genuine-88861.../dp/B00BK7LR36

  5. #5
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    Thank you for the helpful comments. I've order two bottles of X66P and will report back.

  6. #6
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    Custom VENTING for ccv ....requires custom metal fabrication....Doing so, may void many 'state' emissions inspections.....It may not pass emissions...if you alter....just saying....

  7. #7
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    Update: I jacked the X3 pretty high to get the pistons to sit almost straight up and down. Did two soaks with B12 and one soak with GM Delco X66 Top End Cleaner. Effing miracle. Engine went from using a quart every 150 miles to no detectable use in 200 miles. It must have freed up a stuck ring. Very pleased.

    Thank you Marco Zandrini!

  8. #8
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    Yes: now all well and fine....but wait a minute...report back in 5k.....Seriously!

    Your posting here has raised an alarm for any M54.

  9. #9
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    You’re welcome!! Also, try Shell Rotella 6 oil. People at E46Fanatics swear by this oil for their M54 engines. This oil is widely available. Try Walmart.

  10. #10
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    After 1500 miles the engine used almost exactly a quart of oil. A tenth of what it was using. Oil was straight 40 weight. I also replaced the CCV. Car went back to my daughter so will be hard to track the consumption with any precision.

  11. #11
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    I had a deuce of a time with the same issue of oil burning. I ended up using a PCV valve. More details here:
    https://www.bimmerforums.com/forum/s...Delete-PCV-mod
    Bimmer addict since 2016

    Current:
    2001 BMW 525iT

    Past:
    2003 BMW 325xi Auto (sold)
    2003 BMW 325i Auto (sold)
    2001 BMW X5 3.0i Auto (sold)
    2001 BMW 325i 5 spd (totaled)

  12. #12
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    Quote Originally Posted by MarcoZandrini View Post
    The pros over at E46Fanatics use GM Top End cleaner. It’s very strong stuff.

    https://www.amazon.com/Genuine-88861.../dp/B00BK7LR36
    Excellent product, use as directed:
    https://www.youtube.com/watch?v=_Vo4fm0JDPY
    Last edited by MIKYZZ4; 05-15-2018 at 10:47 PM.

  13. #13
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    Rotella T6 5w40 recently changed the formula so it may not help with the oil burning as it once did.

    I recommend the best fix of them all, the legendary O2Pilot mod! It's very simple to do. Hook up a 3 foot piece of vacuum tubing from the back of the intake manifold to the nipple on the CCV valve. The O2Pilot mod increase the crankcase vacuum and makes the rings seal.

  14. #14
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    Just got a couple jugs of Shell Rotella T6 last week for my oil change coming up soon, as well as a Mann oil filter. I'm hoping this diesel engine oil lives up to the hype without ruining my engine! I don't really have a bad oil consumption issue (it's maybe a qt every 4k miles because I got that low oil light when I turned the car off a few weeks back; checked the dip stick - was low - so I put in about a quart and it was good to go again), but I still want to do the O2 pilot mod to help nip the issue in the bud before it gets worse.

  15. #15
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    Use liquimoly oilsaver in the oil any bg44k in the gas. Typically fixes this issue by cleaning up the rings. Do it a few times until it returns to normal. Follow the labels.


    Sent from my iPhone using Tapatalk
    _________

    1980 320i - Kashmir Metallic - Sold in 1993
    1985 535i - Cosmosblau Metallic - Sold in 1995
    1985 535i - 1985-06 - Delphin Metallic - Sold in 2016
    1983 320i - 1982-09 - Kashmir Metallic - Currently own!
    2004 ZHP - 2003-08 - Titanium Metallic - Currently own!
    2000 M5 - 2000-02 Titanium Silver - Currently own!

  16. #16
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    Definitely not better than what was already recommended,
    by both myself and Marco!!

  17. #17
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    Sorry read through the thread quickly didn't notice your responses. I don't question what you guys recommended works. I have personally fixed two m54s with the liquimoly and bg44k.


    Sent from my iPhone using Tapatalk
    _________

    1980 320i - Kashmir Metallic - Sold in 1993
    1985 535i - Cosmosblau Metallic - Sold in 1995
    1985 535i - 1985-06 - Delphin Metallic - Sold in 2016
    1983 320i - 1982-09 - Kashmir Metallic - Currently own!
    2004 ZHP - 2003-08 - Titanium Metallic - Currently own!
    2000 M5 - 2000-02 Titanium Silver - Currently own!

  18. #18
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    So your...2005 X3 with a 2.5L M54...has 100k....yes? Seems odd to me that this situation about oil consumption is so diverse!....Is it possible that your M54 engine may have, and has had, a manufacturing defect not followed up and not previously revealed until now? This is definitely not normal...as you have explained.
    Last edited by Eaglesail; 05-22-2018 at 02:18 PM.

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