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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29 Responses to N20 rod bearing

  1. oasis says:

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


  2. oasis says:

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


  3. kr4va says:

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


  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?


  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??


    • 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


  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?


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


    • 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?



      • 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


  7. javier says:


    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!! 🙂


    • 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


  8. AJ says:

    What did the top end look like?


    • 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.


  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


  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


      • 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.


  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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