N20 rod bearing

image Ok here this is that N20 with the engine rattle,,,BMW wanted me to check out the engine to find the problem,,,,so they had me remove the valve cover and check the upper end for any abnormal wear or damage,,,,,then the wanted me to check the rod bearings,,,,,here a pic of the oil pan and oil pump removed,,,,also the rod bearing caps are removed.image Here is a picture of all 4 rod bearing caps,,,,as you can see they are all worn the same,,,,but are biggest worry is how they are worn at the very bottom middle.image Here is a close up of one of the rod bearing,,,,you can see how they are worn,,,,,it’s hard to tell from the picture,,,,but there is almost a copper color to this bearing,,,,,that is bad news,,,,,when you start to see a copper color in a bearing,,,,that is a sign of a worn bearing,,,,,BMW wants me to replace the whole engine,,,,,the bad news it doesn’t pay for a tech,,,,it only pays 16 hours to remove engine and swap over all the parts to the new engine,,,,,that 2 days of work to before a engine swap.

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55 Responses to N20 rod bearing

  1. oasis says:

    What happens to the old engine that only needs rod bearings?

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  2. oasis says:

    Also is there any additive that can be used to stop rod bearing wear.

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  3. kr4va says:

    i think all dealers screw techs on warranty- sucks.,,,bearing problem—, bad oil,? no changeee oil? spark knock? soft bearing material?

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  4. Tyler Kummer says:

    What kind of noise was the engine making? We got one that ticks/knocks at a warm idle (not direct injection noise) that sounded more like a timing chain. Found the chain worn and replaced with guides and tensioner. Noise is still there. Pulled the rod bearings and found wear patterns similar to yours. Beginning of rod knock maybe?

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  5. jinhan83 says:

    My local BMW dealer is quoting about $20-25K for this work and I’m praying my extended warranty comes through on this. AND I just bought a 2012 328i with 57K miles from one of those luxury auto dealers and they claim they did a thorough inspection. Don’t have the final estimate yet but the number is what my service advisor is estimating. I’m also in talks with the original dealer to figure out a solution.
    1. Can you just replace the rod bearing and the effected parts instead of doing an engine swap?
    2. Is this a common problem?
    3. What causes this problem?
    4. Does an engine swap must be completed at certified BMW dealer?
    4. What was the total cost of the engine swap?
    5. What would you do in my situation??

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    • Hi sorry about your problem,,,,I know it must be frustrating,,,
      1) yes you probably can replace the rod bearing,,,but you would have to tear the motor apart to get the crankshaft number for the rod bearing size which isn’t easy,,,,,and I haven’t heard of anyone replacing rod bearing only yet.
      2) no it’s not a common problem,,,we see the rod bearings or timing chain assembly go bad.
      3) we don’t know what causes the problem yet,,,,BMW hasn’t said what the problem is,,,,is it a defect ,,,is it driving it to hard,,,,we don’t know at this time.
      4) no engine swap can be done any where,,,the warranty might change on the engine,,,,you might have to ask the dealer ,,,,,if the warranty changes on the engine if a independent does the repairs.
      5) don’t know the cost,,,,as a tech we don’t see the price,,,,I can tell you it only pays me 16 hours to swap out the engine and get it running.
      6) what should you do is a tuff one,,,,see what the extended warranty company says and what they will do for you,,,,also talk to the dealer ask about some kind of goodwill program,,,if the could help with a discount,,,,maybe they eat the motor and you pay the labor..,,,,good luck,,,I hope this helps

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  6. Stuart says:

    Looks like Clevite now have a coated high performance upgraded bearing set. Speculating here but it could well be that the rod bearing tolerance isn’t providing enough clearance, and like other previous BMW engines we too are seeing premature bearing failures. Couple that with some unique oil pressure situations (drop under heavy breaking and high g corners) that have been identified by race teams and rod bolt stretching and we have a perfect storm.

    I’m planning to push this engine some with a larger turbo compressor wheel and tune, so I’m looking at a tear down to replace bearings with Clevite units and rodbolts with Carr or ARP versions. Maybe even go to forged pistons and rods 😉 I’d definitely replace the timing and oil pump chains while at it.

    Anything else I should consider? Maybe head studs or closed deck?

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    • Yes you can change the rod bolts to ARP bolts if they make them for the N20 engine

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    • Fred says:

      I have a 13 N20 torn apart all over my bench. Searched high and low for aftermarket rod bearings and rods. Does any of you fine folks have part numbers or links to these?

      Thank-You!

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      • Stubok says:

        CP Carrillo do a set of upgraded Rods and Pistons. Easy enough to find online. I went for standard bore and 10:1 CR but there are a few other options (84.5mm 9.5:1Cr). I’ve also Seen king bearings for the n20b20 on eBay too.

        Only issues I’ve discovered… the block (bottom of cylinder) has to be notched or ground down to accommodate the larger CP Rod. I have a picture from another builder that did this and sleeved the block.

        My build was pushed out a while, as I bought a house.

        Liked by 1 person

      • Stubok says:

        Oh and one other thing… apparently BMW says you can not hone the arc spray weld cylinder coating. I’ve seen various reports that it’s only 0.2-0.4mm thick. So honing would be a problem. So apparently to do the job right and set the right clearances for a high performance street engine (i’m aiming for 500hp at the crank), you really need to sleeve the block. The pictures of the build engine I’ve seen used dry sleeves.

        I also reached out to ARP to find out if the had done a set of Head and main studs, but not yet. Shouldn’t be a problem though.

        Liked by 1 person

      • No I’m sorry I don’t,,,,I only use factory BMW parts

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  7. javier says:

    Hello

    As per your experience, is this a common issue in the N20’s? In any case, in your opinion, at what mileage this issue is expected to happen? In fact i’m still thinking about my low oil pressure issue -in progress, next results in the coming days from the shop-, and i was wondering (and afraid :-() whether a slightly worn crackshaft bearing may be the reason: “Low oil pressure” only at relatively low rpm’s, always with the oil warmed-up, 78000 miles..:-/ …

    (nostalgic about my previous E36 325i which is still running around with more than 320 Kmiles on the clock without never have known any of these issues!! 🙂
    Thanks!
    javier

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    • The rod bearing problem was not a common problem,,,you problem with the oil pressure coming and going just doesn’t make any sense,,,,I know on the older engines we never had these problem,,,,I don’t understand what the problem

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  8. AJ says:

    What did the top end look like?

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    • Sorry we didn’t check the top end,,,,when I removed the rod bearings I didn’t go any further,,,,,BMW doesn’t pay me to tear down the engine once I found the problem.

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  9. Mark Kamner says:

    Do you know why newer n20 engines are quieter than older ones. My friends n20 on his 428 is much quieter than mine on my 328

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  10. Michael says:

    Hey there! Quick question.. I’m a bit concerned about a knocking sound on my 2012 X1, but I’ve been told this is somewhat normal and not a concern as it disappears when revved and driving… seems to only be at idle. I’ve attached a video, just wondering if this is something to be concerned about? It’s pretty young at only 42k kilometres

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      • Thanks for the video,,,,,everything sounds normal,,,question for you is that knocking noise there while driving up a hill and with a load on the engine and boosting that’s when you can tell if you have rod knock,,,,,it doesn’t have to be a big hill,,,just need a load on engine and turbo boost,,,,if there is no knocking you are good,,,,,second thing the rod knock on that engine was very rare,,,,we only saw that on a couple engines very early N20 engines.

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  11. Michael says:

    Great to hear, thanks! Actually drove up a few hills today with winter tires and rims loaded in the back and you can’t hear anything in the cockpit, it was just that knocking at idle and low rpm that had me worried. Much appreciated!

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  12. William Yeo says:

    It is possible to change the rod bearings without removing the engine from the car?

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  13. William Yeo says:

    Do u have an email or skype or something? Would like to ask u abt the procedure.

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  14. Bruce Borstmayer says:

    I bought a 2013 528ix with a bad engine. Original owner had oil pressure light and then engine stopped. I have put this chain of events together: Extremely small dia oil pick up screen 1″ dia. It was plugged with sludge. That is what happens with long oil change intervals. I pulled off thevalve cover and discovered the intake cam sprocket had been rounded off from chain sliding over it. Of course all the chain guides had broken and were in the oil pan. They broke when the timing chain rode over the sprocket teeth. I pulled one of the intake cam bearing caps off and found it was badly scored. In fact just turning the engine over and the timing chain slide over the sprocket so it definitely was seizing from low/no oil pressure. I just pulled the head off and it looks like a valve or two might have touched the piston but really nothing to be concerned.
    So I would say that the tiny oil pick up screen with long change intervals did this engine in. I’ll bet many more of them had same issue. Probably not so much timing chain stretch as low oil pressure causing galling so intake need more power to turn.
    The engine had 77,000 miles. Just over the warranty limit. The poor guy lost over $20k on this car.
    Cars are my hobby. I have rebuilt BMWs: M42, S52, S54 and now this. (I didn’t really want to work on this car buy no one wanted to buy it so I did)

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    • The long mileage between oil service doesn’t help,,,,but what we find out is that people don’t even do the free oil services,,,,I have seen some car go over the oil service by 15k miles and then we find sludge and damage to the engine.

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    • Jeff Dowler says:

      Can the intake cam and ledgers and caps be rebuilt? I am buying and bad N20 with the same issue. Did you repair the engine or just replace it?

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      • No you can not rebuild them,,,you have to replace them

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      • Bruce Borstmayer says:

        I bought another head only to find the exhaust cam and intake cam bearings were both scored although not as bad as my intakes were. I’m thinking I might be able to hone the bearing caps and polish the cam bearings.
        I was looking at another head and that one was not scored but they had not saved the bearing caps! I’m thinking finding a good head will be difficult. I have moved the car into storage until I can find a good head.

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      • I’m sure its going to be hard to find a good cylinder head

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  15. Learner says:

    Hi, in this page you mention about Rod bearings, is there a difference between this and crankshaft thrust bearings? With any early rod bearing issues, what kind of sounds would you be looking out for on a cold start and at any revs (on idle) if applicable? Thanks

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    • Yes there is a difference between rod bearings and crankshaft bearing,,,,rod bearing noise usually happen warm or cold and while driving,,,usually up a hill with a load on the engine you might here a knocking noise.

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      • Learner says:

        Hello, regarding a 320i (2012), would you only change rod bearings if you heard a knocking noise or other outer symptom (e.g. Metal found in the oil filter, etc) or would you consider getting them changed at a certain mileage as a preventative measure? Also do you know if the newer rod bearing parts (for the bottom end) solve the issue involving rod bearings as has the part number changed ?

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      • I would remove and inspect the rod bearing and main bearing and see where the metal is coming from,,,and if there is any damage to the crankshaft journal.

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  16. Learner says:

    Just to clarify the previous message, If you didn’t find any metal in the oil filter or hear any outer symptoms like a knocking noise, then is OK and best to leave the engine as is (I.e. Not to open engine apart and you would not inspect rod bearings to examine their appearance) ?

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    • If there is no metal in oil filter and no knocking noise,,,then I would not check the rod bearing,,,I would only check the rod bearing if the oil pan was removed then I would check them

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  17. Andriy says:

    Hello, looking for advice and thank you for posting this blog, very helpful.
    I have a knocking N20 out of Z4 and I’m fairly certain that it needs the rod bearings replaced. I assume I can replace them from under the car by removing the oil pan which will give me access. Now after reading the TIS on this they mention crankshaft crank pins, do I have to do anything with this? I’m a home mechanic and I’m not sure what they mean exactly by saying “All crankshaft crank pins are classified” and can I identify this without tearing the engine down? Do I need special tools?

    Also, please give your opinion on the actual noise coming from the engine:

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    • Thanks for the videos,,,,it’s hard to tell but I think the noise is coming from the head,,,,maybe valve train noise,,,maybe take off the valve cover and check out the camshaft lobes and valve spring,,,,,sounds like something might be broken cylinder 3

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      • Andriy says:

        Thank you for your suggestion. I will do this before dropping the subframe for the oil pan.
        In case I do still have to change the rod bearings, is there a way to find out which Connecting Rod Bearing I will need (I know that it’s on the first crank web, but I don’t think i will be able to see that from the oil pan.

        Thank you!

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      • Good question,,,I don’t think you will be able to see it from the oil pan either,,,we don’t replace rod bearings anymore,,,,they just have us replace the whole engine for liability reasons.

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      • Andriy says:

        So, I took your advice and took the valve cover off. I checked the loves and valve springs and everything looks fine (although, if you can tell me what specifically to look for, i’d appreciate it very much).

        What I did notice is that the chain is VERY loose in a certain position. When I spin the engine half to a full turn, the chain becomes very tight again. Could this be cause the noise by itself? What would be the first thing to go with the timing chain like this? Rob bearing?

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      • Thanks for the video,,,I wanted to see if the camshaft lobes are ok and not damaged,,,what was strange on last video when you disconnected the ignition coil on cylinder 3 how the knocking noise changed.,,,,the timing chain having that much slack is crazy and then it get tight when you turn it so the chain tensioner is building pressure again,,,,I have never seen that much slack in the chain where you can put your finger under it.,,,,I think you might have a couple problem,,,,timing chain issue,,,and I don’t know about this knocking noise it could be rod knock hard to say?

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      • Andriy says:

        Would you attempt to fix it or just go for a new engine? I’m willing to spend the time to replace the chain and do the bearing, but I don’t want to spend $800 worth of parts and not solve the issue. I found a few engines around $3500 with around 20-30k miles on them.

        Thank you for your suggestions through this. If you have any other advice, please let me know!

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      • I would probably go with a used engine,,,,just because I worry about that knocking noise and we don’t know what going to fix it.

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  18. Wilson says:

    Hi there, I have a N20 with slight knocking noise when car is in drive or reverse you can feel the vibration when it’s in drive or reverse but not in park or neutral(or turning on the ac). Car sounds fine when it’s in park and no vibration, the engine mounts was replaced couple months ago. I would like to know is this knocking noise and vibration caused rod bearing or something else, this engine also needs a timing chain guild rail replacement and a new turbo soon, if it’s the rod bearing going bad is it more economical to just put a low mileage used engine in it?
    Thanks!

    Idle noise when car is in park: https://youtu.be/ETCUalFulwo
    Idle noise when car is in drive: https://youtu.be/kNjQOKboy8M

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    • Thanks for the video,,,,,ok it’s hard to tell by the video what I am hearing,,,,,that being said,,,,,you said the noise is not there when it is in park,,,,but it does it in drive and reverse,,,,that doesn’t sound like a rod knock,,,because a rod knock would happen all the time and would be real bad when driving with a load on engine like going up hill,,,,you did say it needs a timing chain and rail,,,that could be your noise and vibration

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