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Thread: 2008 M5 Oil consumption.

  1. #1
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    2008 M5 Oil consumption.

    (135K miles)

    I have a very strange behavior on my car's oil consumption (using 10w60 always).

    About 2 years back, it used to give me around 1400 miles per Quart.

    Now, its very strange. On having a reading of +1.0 on the meter, i start driving
    the car. I see the oil level drop by about 0.1 for every 100 miles evenly.
    By 500 miles, the level is now at +0.5. This is when actions starts !
    From 500 miles to 650 miles, it goes from +0.5 to +0.0
    The car eats up half a quart in just 150 miles while it takes 500 miles
    from full to 0.5 quarts. Any idea whats going on ?

    This has been happening for the last 6 months now.

  2. #2
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    Sounds strange. I know that most oil consumption happens over 6000 rpm. S85 is known to consume oil at high rpm. What are you doing during this 600 miles? Otherwise you have a dead cylinder, rings or valves. I would do a compression test. I’ve heard of the charcoal canisters causing oil consumption problem too.

  3. #3
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    i drive it like a mule - slow. never really ripping it around. Just in its standard D (Drive) mode, never speeding, maintain around 2000-3000 RPM at most.

    how can it be dead cylinder -- the gas mileage is around 15-16mpg, and none of the cylinders show misfires in Torque PRO.

  4. #4
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    Quote Originally Posted by sshivaram View Post
    i drive it like a mule - slow. never really ripping it around. Just in its standard D (Drive) mode, never speeding, maintain around 2000-3000 RPM at most.

    how can it be dead cylinder -- the gas mileage is around 15-16mpg, and none of the cylinders show misfires in Torque PRO.
    Dead cylinder doesn’t necessarily cause a code. And driving the car like that is very hard on it. Btw. You need to “clear it out” and get carbon build up off but doing some high rpm pulls. Most importantly auto shift is abusive to trans, should always drive in manual mode. Only thing auto is good for is gas mileage and if your concerned with that I would purchase a different car lol. 2 things I would do, check intake plenum for oil and do a compression test. Just taking the spark plugs out should show you which cylinder has problem just by how much oil there is on the electrode. If there’s oil in the plenum then change pvc and related parts first.

  5. #5
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    I do take it WOT , but for the last 2 months been driving it in 2-3K RPM range only just to see oil consumption.
    I changed the spark plugs about 4 months back, and they were clean. Will do a compression test, and also
    spend some time checking the intake plenum. My car's idle actuator on bank1 is dying, so i hit the "DSC"
    and lower power mode all the time now. Just trying to survive for a few more weeks till i get my E90 ready.

  6. #6
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    Think of it this way. The oil has to be going somewhere, right. So either it’s leaving through the combustion process or it’s leaving it on the ground. I find it hard to believe that the spark plugs were completely clean. I’d like to see a picture of them. But if you have actuator problems then perfect time to check plenum for oil.

  7. #7
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    How is your exhaust color? Is it smoking? If not, look for leaks.

  8. #8
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    Quote Originally Posted by Johnbennett103 View Post
    How is your exhaust color? Is it smoking? If not, look for leaks.
    Car runs super clean, and the exhaust looks clean too. Nothing visible.
    When car is running hot, i have briefly sniffed the exhaust and there is no smell
    of gas. When i hold my hand, i can feel the moisture coming out(steam
    from the exhaust, after the catalytic converter action).

    I am stalled with few other issues with the car, so have put this thread on hold lol.
    Other issues: its SOS/Bluetooth/Radio was dead, and so was the RDC TPMS module.
    Gonna update this forum with details.

  9. #9
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    Countries have invaded each other and fought wars over oil.
    I don't know what I should do to protect the oil in my M5's engine.

    Oil level went to +0.0, and I added 1 quart. It showed exactly at +1.0.
    I drove it for many days, and was burning oil at the rate of 0.1 per 100 miles.
    It was at +0.7 and i drove about 26 miles.
    When i stopped the car, it shows +0.1, so it consumed like 0.6 in just 26 miles.
    This is very frustrating !

    The uneven oil consumption bothers me more than losing all this precious oil.

    I have no clue how the oil is disappearing so fast. I don't see any oil dripping anywhere, no leaks.

    I will try to take out the spark plugs and check them this weekend, all of this takes up time.

    - - - Updated - - -

    Quote Originally Posted by Sundaycruzer View Post
    2 things I would do, check intake plenum for oil and do a compression test. Just taking the spark plugs out should show you which cylinder has problem just by how much oil there is on the electrode. If there’s oil in the plenum then change pvc and related parts first.
    Will try this, thanks for the suggestions.

  10. #10
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    S85 and S65 are known for oil consumption. A lot of old timers will tell you to drive it hard on a regular basis, as they say this helps seat the rings better and will reduce oil consumption.

    Just a story, my old shop foreman had an E46 M3. When he bought it, he averaged about a quart every 1k-1500 miles. He then started racing the car at the track a few times a year. Since then, he says he goes 4-5k miles before having to add any. I've heard similar things from others as well. It always seems like the people who baby their cars tend to have the most issues overall.
    ASE and BMW Master Certified Technician

  11. #11
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    Makes sense , let me try a few trips at high RPMS. i am scared to bust something. it has 135K miles now.

  12. #12
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    135k miles? Have you had the rod bearings replaced?

    Sent from my Pixel XL using Tapatalk
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  13. #13
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    Quote Originally Posted by White94RX View Post
    135k miles? Have you had the rod bearings replaced?

    Sent from my Pixel XL using Tapatalk
    No, I don't think it was changed. I bought it at 97K. I don't rip it around too much. Its now my daily driver. Its idle actuators are acting up now, and i get the DSC/Reduced Engine power sign now. I let it cool off and it works perfect again. The idle-valve error happens only when i run the car for long, its all heated up, switch off the car and turn it right back on. Otherwise, it never shows up. I can drive it in my commute daily, and when i come back, its all cooled and ready to go again. Till i fix my 325xi, this has become my daily driver.

  14. #14
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    Well if you're at 135k miles on original rod bearings, you're driving on borrowed time. When I had my M5, I changed them at 96k and most of them were down to the copper. I changed a set on a customer's car at 70k that were starting to wear through to the copper.

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  15. #15
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    Quote Originally Posted by White94RX View Post
    Well if you're at 135k miles on original rod bearings, you're driving on borrowed time. When I had my M5, I changed them at 96k and most of them were down to the copper. I changed a set on a customer's car at 70k that were starting to wear through to the copper.

    Sent from my Pixel XL using Tapatalk
    I hear you, and am very scared. Just can't afford any downtime on my M5 right now. Would a oil test with copper/lead residue help determine over 2 months if the copper is grinding in the bearings ? I was reading about all of this yesterday. I don't push the car anymore, just hovering no more than 3000RPM.

  16. #16
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    That will tell you something. Not sure if it's solid proof or not. If you need an oil sample without doing an oil change, there's a drain plug on the oil filter you could easily get some from.

    Rod bearings are a maintenance item on S engines, especially S85's. Maybe it's not common knowledge like I thought. Best piece of advise is to always let the oil get to operating temp before driving hard. The oil is so thick when cold, and the rod bearing clearance is so tight, that's when all the wear happens.

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  17. #17
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    Technically, there should be no copper in oil. Presence of copper indicates wear limits on the rod bearings. My oil filter drain plug is frozen shut, and has been damaged by previous attempts i think, i have to take the filter out and catch that oil about half quart, and then top it off.

  18. #18
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    The confusing unreliability of our M5 continues.
    Oil had dropped to 0.4, and i added half a quart.
    For over 300 miles now, its stuck at 0.4, and doesn't show the new oil that was added.
    I rest my case ((

  19. #19
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    The S85 engine, as mentioned by many above, burns oil. The oil sensor is also know to be erratic. A good rule of thumb with these engines is to consider 1qt burn per 1500 miles. I usually drive between 3-5k miles between changes. I also always drop in 10qts of oil in every change and I too get the warning about too much oil. I just did a change yesterday and it's reading 1.5. I guarantee by the end of the week it will find its way down to closer to 1.0.

    After long roads trip (which I have an 800 mile one this Friday) it will show up to .2 less than at the start. I have put over 10k miles on my E64 M6, that now has over 105k miles on it (I bought the car in May 2019), and have not had any REAL issues with the oil.

    And before anyone asks, yes the rod bearings have been replaced and all the known issue parts of an S85 with SMG3 transmission have been replaced.

  20. #20
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    Back to this thread - i read up about PCV valves. This oil consumption problem sounds like valve stuck open. Its sucking up all the oil, and as oil level drops, more oil droplets are created in the crankcase which are getting burned up. I have ordered PCV valves and will replace them. I don't think they have ever been changed on this car ! Have no history on this car actually.

  21. #21
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    Quote Originally Posted by Sundaycruzer View Post
    Dead cylinder doesn’t necessarily cause a code. And driving the car like that is very hard on it. Btw. You need to “clear it out” and get carbon build up off but doing some high rpm pulls. Most importantly auto shift is abusive to trans, should always drive in manual mode. Only thing auto is good for is gas mileage and if your concerned with that I would purchase a different car lol. 2 things I would do, check intake plenum for oil and do a compression test. Just taking the spark plugs out should show you which cylinder has problem just by how much oil there is on the electrode. If there’s oil in the plenum then change pvc and related parts first.

    " If thereÂ’s oil in the plenum then change pvc and related parts first." It was the PCV valves ! Changed them, and the oil consumption is fixed now. I see 300 miles on the cart and oil level is at +0.9 on the display.



  22. #22
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    Good to hear. Next step is to change the rod bearings before you destroy the engine. And make sure to replace the high pressure vanos oil line while you're in there.
    ASE and BMW Master Certified Technician

  23. #23
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    Update: Oil level is now at +0.8 after 439 miles - that is a significant relief for me.
    Car runs so smooth - was ripping it around today.

    Now rod bearings - I hope and pray they are ok. I need some breathing time before i can take things apart in this car lol.
    Car has 137K miles now.
    Also fixed the Throttle actuators with new plastic gears, car looks super clean.
    BTW, i bought this car 3 years back when it had 97K on it. Previous owner had decat this car - just discovered it last week while
    replacing the diff seal.
    I have 2 used exhaust manifolds with cats from a 2010 M6 with 76K miles, gonna put them in and save the decat exhausts for another day or put them on sale
    on ebay. I want the car to run super clean, environmentally too.

  24. #24
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    You're driving on borrowed time my friend. When I had my M5, I changed the bearings at 96k, and almost all of them were wore down into the copper. I did a set at 65k and were starting to wear through the top layer and beginning to show copper. I have seen more V10's self-destruct from spun bearings that I could say. It's not something I would risk. Last I checked, a new engine was still over $20k.
    ASE and BMW Master Certified Technician

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