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BMW 3-Series Oil Questions

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Comments

  • MrShift@EdmundsMrShift@Edmunds Posts: 43,626
    It's a fancy PCV valve. You are correct, the tecnical service bulletin does refer to these cracking in freezing weather.

    You have to be burning the oil or leaking it. There is no other explanation under the laws of the universe (as we now know them) :P

    Cylinder leakdown might not show worn valve guides or bad valve stem seals.

    One quart every 1K is just about minimum tolerable level.
  • sunilbsunilb Posts: 407
    Thanks for the lead(s)... if it turns out to be worn valve guides or bad seals, any rough idea on how expensive this may be to fix?

    Can this be discovered through another test or just visual inspection with a trained eye?
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,626
    Sometimes you can do a road test with another car following to observe. What you do is warm the car up, and then put it down a long, long hill (after revving it up going up the hill)....you take your foot off the gas for a while and let the engine drag the car down, and then you PUNCH the gas briefly, and if you have worn guides/seals, the car behind you will observe a puff of blue smoke out your tailpipe.

    What you have done is create a situation of high engine vacuum (coasting downhill in gear) and then relieve it by hitting the gas.

    Valve stem seals might not be too expensive (not sure on procedure on your engine) but badly worn valve guides require removal and re-machining of the cylinder head.
  • kominskykominsky Posts: 850
    "You have to be burning the oil or leaking it. There is no other explanation under the laws of the universe (as we now know them) "

    As soon as I put the finishing touches on my 100% efficient machine, I'll tackle this one. ;)

    Thanks!
  • sunilbsunilb Posts: 407
    Well, the mechanic says that he cannot find leaks anywhere, though he said to check the valve guides would require taking apart the engine and would be quite expensive (he checked for smoke out the tailpipes and didn't see anything).

    He's suggested changing the oil separator valve ($120 part + $150 in labor) as that might be the culprit, and monitoring it (ie, the oil level). He said that there's little way to know if this is the real problem until he pulls the old one out.

    Thoughts??

    Again, this mechanic has always been straight-up with me so I have little reason to suspect that he's trying to empty my wallet.

    That being said, this is getting to be a more expensive situation than I would like (especially if this doesn't solve the issue). I was (am?) hoping to keep this car to 150K... but I don't know how feasible of an idea this is.
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,626
    The oil separator explanation still makes no sense. It still has to be leaking or burning. If the oil separator were clogged, that would cause excessive internal crankcase pressure, and then oil would be forced out of the gasket or out the tailpipe. So you'd still have a leak or visible oil burning.

    Perhaps it could be the oil separator and perhaps you can't see the blue smoke while you drive?

    I think the car needs to go to a shop that knows how to diagnose worn valve stem seals and guides or can insert dye into the oil and then shine a black light on the engine to spot the point of exit.

    I get the sense nobody's really trying here, just guessing. That oil separator installation isn't that cheap. What if he is $300 wrong?

    We also have this method:

    Vacuum gauge testing
  • js330xijs330xi Posts: 2
    I have had a similar issue. I would change the oil every 7000 miles and never had the light come on until around 48000 miles, then it would come on after 2K miles. Now the car has 100K on it and the light comes on between 800 miles and 1500 miles needing a quart each time.

    I was told by dealer BMW spec was 1qt per 1000 miles while the car was under warranty. I was told today that BMW spec is 1qt per 700 miles (funny how this has changed now!). I have been documenting this for the last 50K but it has not really gotten me anywhere. There is no consistency about how many miles to the quart I get.

    BMWNA paid to have a leak down test and pressure test done at 98 or 99K (just recently) - everything was in spec and no problems found. Prior to that they replaced the the oil sensor, the cyclone valve, the oil filter housing, and the head gasket (I paid for head gasket, but it was a super tiny leak and didn't change the oil consumption)

    In the end it still uses 1qt every 700 miles to 1500 miles. It drives great so it isn't a problem - but a concern - at this point I give up until something drastic happens to the engine.
  • pdude1pdude1 Posts: 47
    Anyone know an easy way to check the oil w/o a dipstick? Just wondering in case the computer goes out some day or just for sanity check to know that the computer is actually working!
  • bdkinnhbdkinnh Posts: 292
    There's no way to check the oil except via the computer.

    Other than having the engine seize up, that is.
  • pdude1pdude1 Posts: 47
    Oh great...that's how I lost my lost engine. Cam's seized and that screwed up the top end. Didn't feel like fixing it. Well I'll have to hope that computer keeps on working!

    Thanks for the feedback.
  • shiposhipo Posts: 9,152
    ..there is another way.

    The dealerships drain the oil, measure the results, figure an extra liter (or there abouts) of oil is in the oil filter, and you have your results. ;)

    Best Regards,
    Shipo
  • pdude1pdude1 Posts: 47
    But if I drain it, then I can only tell if I was short. Trying to fgure a way to tell if I'm short w/o relying on the computer. bummer..
  • cdnpinheadcdnpinhead Forest Lakes, AZPosts: 3,206
    "But if I drain it, then I can only tell if I was short. Trying to fgure a way to tell if I'm short w/o relying on the computer. bummer. . ."

    Yessir, you are exactly correct. It's bad enough to have no dipstick, but when the substitute proves to be unreliable and very expensive to repair. . .

    That, plus the run-flat tires, explain why the car I lusted for over the past four years isn't in my garage at the moment.

    Now, to add to the joy, the prices are up and the residuals are down.

    Gotta love them BMWs.
  • sunilbsunilb Posts: 407
    Thanks for the response(s)... given that I had left my car with the mechanic for two days (very inconvenient for me professionally). I went ahead and had him replace the oil separator (no offense, Shipo). Not sure if it will help, but I'll keep monitoring it.

    js330xi-- thanks for the info... on one level, this is good to know; and on another level, this is bothersome that it's just something to "live with". But, sounds like your car is still driving and operating fine, despite the consumption.

    Seriously... this means that by the time you get to the regular oil change (7500 interval), then you are in fact draining out relatively new oil (ie, the oil put in at the previous oil change is already gone and replaced by these 7 "top-ups"). Bummer.
  • shiposhipo Posts: 9,152
    "Thanks for the response(s)... given that I had left my car with the mechanic for two days (very inconvenient for me professionally). I went ahead and had him replace the oil separator (no offense, Shipo)."

    Uhhh, what was I supposed to possibly take offense at? :confuse: Personally I think the oil separator and/or anything else to do with the PCV system is a very good place to start when there is unexplained oil consumption, regardless of what type of engine or who built it.

    Best Regards,
    Shipo
  • sunilbsunilb Posts: 407
    Uhhh, what was I supposed to possibly take offense at?

    Sorry... I meant to apologize to Mr Shiftright, who asked "what if he's $300 wrong?".
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,626
    Oh a mere rhetorical question, that's all I was posing....I was wondering what he'd say if it didn't work. But I hope it does for your sake :)
  • idoc2idoc2 Posts: 78
    I'm unclear on how a "liter (or there abouts) of oil" can be left in the filter. I have 2007 328xi. I am having the dealer change the oil for "free" during initial maintenance program at the 15K+ (aprox) intervals as called for by the car's computer. I change the oil myself at the intervening 7500K interval. First the oil is drained from under the car via the bolt opening in the pan. Then the filter housing cap is removed. At this point there is perhaps 30ML of oil remaining in the housing. As I assume you know BMW oil filters for this engine are not constructed in a self contained cartridge as is typical of most other manufactures. They are simple filters and when removed are only moist with oil holding I would guess no more than 20ML of oil. I look forward to your reply.
  • shiposhipo Posts: 9,152
    Hmmm, that's odd, when I screwed off the caps of the filter canisters on my BMWs, I always found them to be basically full. After pulling the filter element out (which holds a fair amount of oil in-and-of-itself) I always had to extract considerably over a half of a liter of used oil before the canister was completely empty. That yours was basically empty has me at a loss. :confuse:

    Best Regards,
    Shipo
  • According to BMWUSA the following oils are approved:

    Castrol Syntec European Formula SAE 0W-30
    Mobil 1 SAE 0W-40
    Pennzoil Platinum European Formula Ultra SAE 5W-30
    Valvoline SynPower SAE 5W-30

    Here's the link:
    http://www.bmwusa.com/Standard/Content/Owner/SyntheticEngineOils.aspx
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