Engine knock - Rod bearings issue, savable without an engine replacement?

Important:
Current miles: 68k
RB changed from the dealership at: 58k
Known issues:

1. 2 Engine coils causing misfires

Hey guys, on Sunday my e92 M3 2008 (68k miles) started making engine knock noises.
Rod knock noises: https://imgur.com/a/s5locii
Images here: https://imgur.com/a/L2i62zs

I bought the e92 M3 at 59k miles and made sure that the dealership replaced:- rod bearings;- throttle actuators. They did, so I was at peace knowing that they wouldn't have failed. But here we are, 9k miles after.

I've always made sure to warm it up before actually driving past the 3k RPMs, but honestly, it was pretty rare that I would've pushed my car as I had it as my daily drive.

I was taking some time before replacing my engine coils because of misfires on 2 of my cylinders, wanted to get a cheaper option from the £1.600 that my trusted mechanic proposed me, so I started looking on eBay, but didn't come to replace them.

Wen through an engine oil change 2 months ago roughly, and I didn't get any message from the mechanic saying "There's some metallic flakes in your oil, you'd need to get your rod bearings checked", which is something I was thinking about, but then again only changed the RB 9k miles ago.

And here it comes the last day of its usage. On Sunday, as I was on the highway, I started pushing her at 6/7k RPMs, and out of nowhere, I start hearing engine knock noises. I was genuinely surprised and not convinced that the issue was my rod bearings, as the dealership replace them before I bought the car, 9k miles ago. The car was running fine but of course, the engine knock was there once I would've gotten at 2k RPMs.

Took my car to my trusted mechanic, and he straight away says "Rod bearings", checks the oil and there are some metallic flakes in the engine oil filter, he straight away says "You need an engine rebuild, £20k roughly.", even if the car is actually running fine as of now, but then again I can't see what's really happening in the engine.

The mechanic didn't go through a deep inspection of the state of the RB or the crankshaft, he just saw the metallic flakes and stopped there stating that the engine needed an engine rebuild or a new engine.

Mortified, I start doing some research, and I actually find people saying that it could possibly be resolved just by changing oil, oil filter, rod bearings and possibly the crankshaft.

What do you guys think of this? Should I ask a different mechanic to go through an inspection? Do I really have to go through an engine replacement spending 20k, or is it still doable to save her?

Who told you the rod bearings were changed? A used car dealer, or previous private seller? or do you have an invoice showing it was done? There are many cases of sellers lying.

Pretty certain that is rod knock. The AC compressor can make a similar sound, so it doesn't hurt to remove the AC belt and confirm the knock is still there. From there you would need to remove the pan and inspect the rod bearings and decide what you want to do from there.

IMO to fix it proper, you want a good crank as any attempted fix to the current one isn't going to be reliable long term. If it's rod knock then for sure the crank is scored.

tdott wrote

Who told you the rod bearings were changed? A used car dealer, or previous private seller? or do you have an invoice showing it was done? There are many cases of sellers lying.

Pretty certain that is rod knock. The AC compressor can make a similar sound, so it doesn't hurt to remove the AC belt and confirm the knock is still there. From there you would need to remove the pan and inspect the rod bearings and decide what you want to do from there.

IMO to fix it proper, you want a good crank as any attempted fix to the current one isn't going to be reliable long term. If it's rod knock then for sure the crank is scored.

tdott Used car dealer. I don't have the documentation nearby atm, it's in my car parked in a closed garage 5 mins away, but IIRC, I don't remember me looking for the Rod Bearing replacement documentation... I'd have to check it, when I'm off from work I'll take a look!

I don't think it's the AC belt to be honest, the sound seems to be coming from the left side of the engine, and IIRC the belt is on the front, lower areas...


> IMO to fix it proper, you want a good crank

That's what I was hoping for really, a good crankshaft (£1.5k) + new RB (£500) + new engine oil (£100) + oil filter (£50) is a big difference than having an entire engine replaced/rebuilt.

I don't really see how my engine is marked as "Totaled" for my mechanic, the engine still switches up, runs "fine" (haven't driven her ever since my mechanic told me the news, only to get her back to my garage), has the rod knock, but at the end of the day, my point of view is that:
1. The metallic flakes in the oil and oil filter aren't "massive", I've seen way worse when looking for these symptoms. New engine oil + new rod bearings + new engine oil filter should perhaps do the job?
2. As the car still runs OK, I'd say that the issues are still fairly limited to the rod bearings and most likely the crankshaft as well. Therefore, new crankshaft.

I will probably take her to a different mechanic for inspection. Probably not even from a BMW dealer, as I'm sure they'd go for the most expensive path just for their sake.

8lueM3 wrote

tdott wrote

Who told you the rod bearings were changed? A used car dealer, or previous private seller? or do you have an invoice showing it was done? There are many cases of sellers lying.

Pretty certain that is rod knock. The AC compressor can make a similar sound, so it doesn't hurt to remove the AC belt and confirm the knock is still there. From there you would need to remove the pan and inspect the rod bearings and decide what you want to do from there.

IMO to fix it proper, you want a good crank as any attempted fix to the current one isn't going to be reliable long term. If it's rod knock then for sure the crank is scored.

tdott Used car dealer. I don't have the documentation nearby atm, it's in my car parked in a closed garage 5 mins away, but IIRC, I don't remember me looking for the Rod Bearing replacement documentation... I'd have to check it, when I'm off from work I'll take a look!

I don't think it's the AC belt to be honest, the sound seems to be coming from the left side of the engine, and IIRC the belt is on the front, lower areas...


> IMO to fix it proper, you want a good crank

That's what I was hoping for really, a good crankshaft (£1.5k) + new RB (£500) + new engine oil (£100) + oil filter (£50) is a big difference than having an entire engine replaced/rebuilt.

I don't really see how my engine is marked as "Totaled" for my mechanic, the engine still switches up, runs "fine" (haven't driven her ever since my mechanic told me the news, only to get her back to my garage), has the rod knock, but at the end of the day, my point of view is that:
1. The metallic flakes in the oil and oil filter aren't "massive", I've seen way worse when looking for these symptoms. New engine oil + new rod bearings + new engine oil filter should perhaps do the job?
2. As the car still runs OK, I'd say that the issues are still fairly limited to the rod bearings and most likely the crankshaft as well. Therefore, new crankshaft.

I will probably take her to a different mechanic for inspection. Probably not even from a BMW dealer, as I'm sure they'd go for the most expensive path just for their sake.

Like tdott said, dealerships lie ALL the time, especially a used one. Find the paperwork if you can and verify if possible.

Flakes in oil certainly sound like a rod bearing issue, but your mechanic is a fucking moron without at least suggesting to drop the pan and remove one or two rod caps. He's either lazy, doesn't know what he's talking about, or a combination of the two. Go to a different mechanic because that's straight deceptive to just say "ROD BEARINGS, NEW ENGINE" without first diagnosing root cause.

Also, don't skip on maintenance like coils/injectors; if you were having issues you should have replaced them instantly so shame on you for possibly exacerbating this issue. Without proper spark or fuel, you can wipe/wash cylinders and cause scoring damage!

Get a second opinion from someone who cares because it sounds like your mechanic can't be bothered to for your sake.

-Duke

8lueM3 wrote

What do you guys think of this? Should I ask a different mechanic to go through an inspection? Do I really have to go through an engine replacement spending 20k, or is it still doable to save her?

IF it turns out to be the rod bearings - which I personally definitely think it is - then "no" an entire engine replacement probably isn't necessary. Providing the crank journals are okay, then usually only new rod bearings would be needed. However, and as DukeofAlexandria already mentioned above, it's probably worth a second opinion. It's imperative you fully document the root cause and findings if you intend to pursue any action against the previous seller who claimed the rod bearings had been replaced. It is still "doable to save her".

I am sorry this has happened to you especially after what you guys have been through in the U.K. with WooFlew. Keep us updated. Do not continue to run the engine or drive the car. Have it trailered to a good and reputable shop capable of and well experienced with S65 rod bearing replacement. There maybe forum members local to you in Nottingham.

Edit:
Found this BMW race prep shop about 50 miles from you. They work on performance cars and/or may be able to recommend similar capable shops closer to you.
https://geoffsteelracing.co.uk/racing-services/

From what I can hear in your video It's 100% bad rod knock .
In other words : Your S65 is 'RIP !

I'm sorry , I wish you the best of luck...

DukeofAlexandria wrote

Like tdott said, dealerships lie ALL the time, especially a used one. Find the paperwork if you can and verify if possible.

Flakes in oil certainly sound like a rod bearing issue, but your mechanic is a fucking moron without at least suggesting to drop the pan and remove one or two rod caps. He's either lazy, doesn't know what he's talking about, or a combination of the two. Go to a different mechanic because that's straight deceptive to just say "ROD BEARINGS, NEW ENGINE" without first diagnosing root cause.

Also, don't skip on maintenance like coils/injectors; if you were having issues you should have replaced them instantly so shame on you for possibly exacerbating this issue. Without proper spark or fuel, you can wipe/wash cylinders and cause scoring damage!

Get a second opinion from someone who cares because it sounds like your mechanic can't be bothered to for your sake.

-Duke

Cheers man, I'll try to find the paperwork in like 2 hours max, hopefully it's there, luckily I've got everything organized in my car.

> but your mechanic is a fucking moron without at least suggesting to drop the pan and remove one or two rod caps

Right! That's what really got me doubtful of his opinion, I mean I know that RB failures are common in this engine, but it's not completely totaled, no smoke, no RB throw, car goes "fine" as of now, and I'm almost positive that the damage is limited as it's still on its early stage.

> Get a second opinion from someone who cares because it sounds like your mechanic can't be bothered to for your sake.

Yes, I've got an appointment with a different mechanic to inspect it on the 2nd of March, I'll get my car towed as I don't want to put further stress on the engine as it is now.

I'll update you guys in the next days, cheers guys DukeofAlexandria DrFerry

Update:

I've checked all the documentation I had in regards to past work on the car, and I couldn't actually find anything in regards to Rod Bearings.
I did find the throttle actuators which was one of the questions I've asked the dealership, but no RB replacement was found.

So, I reckon that the dealership lied in regards to the RB, never replaced, therefore this RB failure is "normal", which really gets on my nerves how all this could've just been avoided if I'd known that the RBs were not replaced 9k miles ago.
Or, they still got replaced but no documentation in regards to the change.

I guess I'll find out on the 2nd of March when the car will get inspected.

I'll post updates in the next days!

Okay, so now you know where you stand with regards to fraudulent representation by the Dealer who sold you the car. You have some time prior to the next inspection to research capable S65 rod bearing replacement experts and shops (garages) in the area.

A suggestion would be to put a call out (make a thread) on the Regional U.K. Forums (scroll down the list to find it) and ask for Rod Bearing replacement shop recommendations in or near Nottingham, as well as experiences from the forum.

While some may say the job is straight forward; there are some horror stories on this forum. So research and parts sourcing are paramount prior to the work actually starting (assuming the rod bearings are toast - which I believe they are).

I personally recommend the BE Bearings with ARP bolts solution. See earlier posts or elsewhere on this forum (stickies). However, at one time these parts were hard to find due to WooFlew.

Sorry for you, mate.

I think that changing a crankshaft is a bad expectation, because the job is pretty massive and pricey.

On the other hand, your crank may still be flawless, and just an RB change could do the job.

Don't wait for specific bearing brand. If the crank is good, go for the easier to find. ACL H or HX with ARP Bolts should be easy to find and cheap solution.

Sure you'd want BE Bearings on your engine, but you don't know what's coming after the job, so don't put too much effort (awaiting time) and money on it.

If you change the RBs now, I'm pretty sure you will want to check them again in like 5k or 10k miles, right? Then you get the BE bearings.

Should any member remember here, there was a guy in this board that had a scored crank and didn't try anything about changing it. Just changed the RBs and drove.

The engine survived a lot of miles, like 5k or so, and we never heard of him again to say that it died. It may not have yet. Who knows.

Thing is:

Will a crank replacement really save the engine? Or may you replace it and after that still have any problem related to the previous RB failure like metal shavings in the galleries? In that case you'd need a new engine.

If the only option is a new engine, then I would totally try only changing the RBs for now.

Sorry to hear about your car OP. The M3cutters UK forum is pretty active, maybe they can help you find a good shop.

https://forums.m3cutters.co.uk/

Good luck!

I'd say no way is that AC comp. knock, at least I've never heard one make a heavy knocking like that.

And I'm sorry to say that I'd put big money on the crank and a rod being toasted .
Sorry to hear of your car troubles 8lueM3.
Just because it's running fine doesn't mean their isn't severe physical damage, it's still running (well firing) fine because the rod hasn't broken yet. Don't run it or it will very soon!

New crank would be a major rebuild anyway, and IIRC a new crank was ~£4k when I looked a couple of years ago. Would probably be cheaper to get a 2nd hand engine.
But I agree that the sump should come off anyway to actually see the damage.

DrFerry
after what you guys have been through in the U.K. with WooFlew

I'm in the UK and you've lost me on that point! lol
Care to enlighten me?

Btw, assuming it is rod knock (would be astounded if it wasn't), the crank is toast.

jvictormp
That guy did report back a few times, and last I heard he was @21k miles on the new bearings! But I don't think his were knocking that badly originally?
But by all means people can double check me on that, this is the relevant thread. [edit] Just listened to some of his video, doesn't sound quite as bad as the ops.

UPDATE:

The car's still being inspected.

Also, when the mechanic guy towed my car to get it to his shop, he mentioned that from what he heard, he thinks he could well be the "Timing Chain".
My car has always "suffered" from having the Vanos timing being "incorrect", as the angle of the <insert piece here, I can't remember what that was> was off of like 2 to 5 degrees, instead of making 180 angle degrees, it does 178, and so on...
With that in mind, he thinks that it could be that issue, stating "the timing chain could well be expanded, and the knock that you're hearing could just be that"

However, I'm not really grappling with the idea of that just being the timing chain, the metallic flakes in the oil suggest that at least one RB has gone bad.

Just waiting for an update now.

8lueM3 wrote

UPDATE:

The car's still being inspected.

Also, when the mechanic guy towed my car to get it to his shop, he mentioned that from what he heard, he thinks he could well be the "Timing Chain".
My car has always "suffered" from having the Vanos timing being "incorrect", as the angle of the <insert piece here, I can't remember what that was> was off of like 2 to 5 degrees, instead of making 180 angle degrees, it does 178, and so on...
With that in mind, he thinks that it could be that issue, stating "the timing chain could well be expanded, and the knock that you're hearing could just be that"

However, I'm not really grappling with the idea of that just being the timing chain, the metallic flakes in the oil suggest that at least one RB has gone bad.

Just waiting for an update now.

Very interesting to see whats going on, if you decide to open the bottom end.

Good luck!

good luck!

Incorrect timing would result in all kinds of errors.

How did you get on with this?

AndyBrad Still waiting for updates really, unfortunately, the guy that I trust had an accident a few days ago, he's coming back to work on Monday.

As of now, nothing has changed really, still waiting for updates, taking ages, but it's not time that I'm scared of

I'll update the thread once I get anything!

Hey guys, I finally have an update, took literally 2 months to get something.

So, there's some damage to the crankshaft:
https://imgur.com/a/PxJiqZF
It's not smooth, there's an odd straight line as you can see.

Also, here are the rod bearings that were mounted on that part of the crankshaft:
https://imgur.com/a/NxNnvXV

Something scratched it from the inside, and I have no idea what that could be.
The mechanic said that it could be possible to investigate what happened by opening the engine block, but he'll go through that if he really has to open it.

Also, unfortunately, I didn't get pics of it, but the main bearing (on the outside part) in the same position shown in the crankshaft pics, looks a bit more "browny", as if it's burnt a little.

As of now, he said that there are two options:
1. Get that part of the crankshaft adjusted, which is I believe smoothing the area involved, and that means the engine will mount bigger rod bearings;
2. Worst case scenario, where the first point isn't doable, we'll change the crankshaft.

He'll be sending the engine on Monday for the first option, so I'll post updates in the next days!

Since you're an 08, that bearing wore past the copper. Nothing scratched it. It's just been worn down and is no longer a bearing.

I don't believe anyone makes oversized bearings for the s65 if you were to grind the crank down. Maybe a polishing will work and wont put you out of spec to use an OEM sized bearing. The point in rod bearing change is that the bearings were spec'd too tightly from the factory. So an OEM bearing on that journal and BE bearings on the others.

You're in rebuild territory though. Inspect the cylinders to make sure they aren't scarred if any of the bearing material made it past the filter.

8lueM3 wrote

Hey guys, I finally have an update, took literally 2 months to get something.

So, there's some damage to the crankshaft:
https://imgur.com/a/PxJiqZF
It's not smooth, there's an odd straight line as you can see.

Also, here are the rod bearings that were mounted on that part of the crankshaft:
https://imgur.com/a/NxNnvXV

Something scratched it from the inside, and I have no idea what that could be.
The mechanic said that it could be possible to investigate what happened by opening the engine block, but he'll go through that if he really has to open it.

Also, unfortunately, I didn't get pics of it, but the main bearing (on the outside part) in the same position shown in the crankshaft pics, looks a bit more "browny", as if it's burnt a little.

As of now, he said that there are two options:
1. Get that part of the crankshaft adjusted, which is I believe smoothing the area involved, and that means the engine will mount bigger rod bearings;
2. Worst case scenario, where the first point isn't doable, we'll change the crankshaft.

He'll be sending the engine on Monday for the first option, so I'll post updates in the next days!

Believe it or not - you were lucky. Some of the other imagur photos seem to show the bearing 'tabs' were worn away (missing) - unless your finger is obscuring the tab. It could mean the motor was just about to spin the bearings and that could've resulted in throwing a rod through the block ("windowing" the block). I see no tabs on this bearing shell..???
.

DrFerry wrote

Believe it or not - you were lucky. Some of the other imagur photos show the bearing 'tabs' were worn away (missing). It means the motor was just about to spin the bearings and that could've resulted in throwing a rod through the block ("windowing" the block). I see no tabs on this bearing shell..???
.

Sorry to ask, what do you mean by 'tabs'?

Also, forgot to upload the outside of one of the RB:
https://imgur.com/a/IjYolL8

One thing that feels weird to me, is that everytime I googled for "S65 RB replacement", the RB were much more "used", the copper part was showing, however, as the RB I've shown in the pics (which is where it has some damage) doesn't really expose any copper, it actually looks almost "new" - I was expecting something like this (Not my pic):
https://imgur.com/a/evyQiTq