N55 rod knock/spun bearing tracking

carguy138 · 12-14-2021, 11:32 AM

Anyone have any new info to share about this?

I've owned my N55 335xi for 7 years and it has been perfect. Occasional track days but doing quite a few more this upcoming summer. Also looking to get a rear LSD.

Just looking for any new info if anyone has any.

Thank!

lforter · 12-25-2021, 12:22 PM

Is there any conclusion around this problem? Have people concluded on what's the problem? Is the rod bearing problem a prevalent one? I bought an n55 dct 2012 with 60K (prod 11/11) to repair as a proyect car (doesn't turn on with hail damage). So I'm thinking if I should replace the bearings or if it's pure paranoia going on here. I have heard that mid 2011 the oil pump and bearings were changed, but I don't know if that affects directly the rod bearing issue. Don't know what's the final verdict on this issue and would like to know if I should do this a preventative maintenance or people are getting paranoic (which is a possibility).

bmw335ie90 · 12-25-2021, 06:15 PM

Quote:

Originally Posted by lforter

Is there any conclusion around this problem? Have people concluded on what's the problem? Is the rod bearing problem a prevalent one? I bought an n55 dct 2012 with 60K (prod 11/11) to repair as a proyect car (doesn't turn on with hail damage). So I'm thinking if I should replace the bearings or if it's pure paranoia going on here. I have heard that mid 2011 the oil pump and bearings were changed, but I don't know if that affects directly the rod bearing issue. Don't know what's the final verdict on this issue and would like to know if I should do this a preventative maintenance or people are getting paranoic (which is a possibility).

N55 Rod Bearings 165k miles (pic) https://www.e90post.com/forums/showthread.php?t=1874335

I'm going to preventatively replace my 72K N55 rod bearings https://www.e90post.com/forums/showthread.php?t=1572184

Seems to be evidence to suggest there are issues on some n55s and no issues on others. Same deal with OFHG gasket replacements causing rod bearing seizure shortly after, camps of people on both sides.

lforter · 12-25-2021, 09:40 PM

Quote:

Originally Posted by bmw335ie90

N55 Rod Bearings 165k miles (pic) https://www.e90post.com/forums/showthread.php?t=1874335

I'm going to preventatively replace my 72K N55 rod bearings https://www.e90post.com/forums/showthread.php?t=1572184

Seems to be evidence to suggest there are issues on some n55s and no issues on others. Same deal with OFHG gasket replacements causing rod bearing seizure shortly after, camps of people on both sides.

It's a shame, there is no specific pattern on the problem? Other than OFHG? It's a shame really. Thought n55 were more reliable, guess I'll have to do bearings as a preventive maintenance which kinda sucks.

whyzee125 · 12-26-2021, 01:03 AM

Nobody has figured it out yet. Consensus seems most of the N55 rod bearing issues happen either after hard cornering on track (almost all street cars COULD have this issue) or after OFHG replacement. Many are just fine even after OFHG, while others aren't. The majority I've seen seem go to between 70-80k miles but there are outliers on both ends.

It's smart to replace your rod bearings while doing oil pan gasket or if you're past that mileage in my opinion.

lforter · 12-26-2021, 08:46 PM

A lot of speculation going on this thread, I have read all the pages and a lot of people are paranoid and aren't thinking straight due to pure anxiety I guess, nevertheless there has been good opinions, just not very organized. I agree with BBK in some notions, I don't think it's a problem inherent to 2011 n55s (even tho the spreadsheet suggest it, its data being taken on an e90 n55 forum where most if not all n55 are 2011 so there is a clear bias) However it does appear to happen to more 11 n55, I have been investigating and anecdotal experiences aren't limited to 11 but most fall in that year, so there is a point to be taken here but not conclusive as the data is too low.

The n54 vs n55 debate is somewhat difficult. Meanwhile n54 is an engine prone to bearing failure, it appears that is not that prevalent as in n55s, the reason being production numbers, personal investigation (as I haven't looked deep into n54 bearing problem) or design failure is not known.

The OFHG procedure does appear to be directly correlated to the bearing issue, several people that spun a bearing have done the OFHG recently. BMW boletin suggest that its related to oil pressure problems. Some cases here suggest that High Gs and oil starvation is a problem that cause bearing to spung.

So, from all of that it does appears to be related with the oil system, I don't think we can pinpoint an exact problem but rather the system as a whole has its weakpoints that when exploited result in spun bearings. Some NXs engines have more weakpoints than others and this result in data having certain patterns but not conclusive ones (more 2011 than other years...).

N5X engines have a probability of a sprun bearing but some iterations have a higher probability than others. How high that probability is is very hard to determine as we have too low data (there's even a possibility that people are going too paranoid about it and that the possibility is rather minimal).

It's sad to say that data is too low te suggest that people should change the bearings preventively (as it could be the case), if we do then people run a risk of damaging an otherwise perfectly good engine, if we don't people run the risk of seizing their engines due to spun bearing.

I believe the right step in this uncertainty situation is that people change their bearings with care and a good mechanic (that know what he is doing) minimizing the risk of fucking their engine, that is if you don't have an engine warranty.

This is the less risky situation in my opinion, but if we could determine a method to detect beforehand that the bearings are wearing too much and seizing is imminent, then we should take that approach before doing any preventive maintenance (oil test, etcetera...)

Finally, people need to chill out before typing. Paranoic text is just deviation from the truth. Nobody wants that to happen to their engine but if there is something to solve we need to breath and think. Also, BMW is to blame for this type of situations.

EDIT: Indeed there's a revision on n55 oil pump starting on 8/11. Cars from 2009-mid 2011 recieve this oil pump 11417573747 meanwhile 2/2012-now recieved 11417613549. Period between 8/11 and 2/12 was a mix between 11417573747 (an updated version it seems) and 11417613549 (not completely updated like 2/12), the reason of the upgrade is not known but should be interesting, anyways im probably going to do bearings and install an acussump afterwards, some may prefer the M2 approach. or perhaps wait and if it wrecks change for a newer n55 version

bmw335ie90 · 12-27-2021, 03:22 PM

Quote:

Originally Posted by lforter

A lot of speculation going on this thread, I have read all the pages and a lot of people are paranoid and aren't thinking straight due to pure anxiety I guess, nevertheless there has been good opinions, just not very organized. I agree with BBK in some notions, I don't think it's a problem inherent to 2011 n55s (even tho the spreadsheet suggest it, its data being taken on an e90 n55 forum where most if not all n55 are 2011 so there is a clear bias) However it does appear to happen to more 11 n55, I have been investigating and anecdotal experiences aren't limited to 11 but most fall in that year, so there is a point to be taken here but not conclusive as the data is too low.

The n54 vs n55 debate is somewhat difficult. Meanwhile n54 is an engine prone to bearing failure, it appears that is not that prevalent as in n55s, the reason being production numbers, personal investigation (as I haven't looked deep into n54 bearing problem) or design failure is not known.

The OFHG procedure does appear to be directly correlated to the bearing issue, several people that spun a bearing have done the OFHG recently. BMW boletin suggest that its related to oil pressure problems. Some cases here suggest that High Gs and oil starvation is a problem that cause bearing to spung.

So, from all of that it does appears to be related with the oil system, I don't think we can pinpoint an exact problem but rather the system as a whole has its weakpoints that when exploited result in spun bearings. Some NXs engines have more weakpoints than others and this result in data having certain patterns but not conclusive ones (more 2011 than other years...).

N5X engines have a probability of a sprun bearing but some iterations have a higher probability than others. How high that probability is is very hard to determine as we have too low data (there's even a possibility that people are going too paranoid about it and that the possibility is rather minimal).

It's sad to say that data is too low te suggest that people should change the bearings preventively (as it could be the case), if we do then people run a risk of damaging an otherwise perfectly good engine, if we don't people run the risk of seizing their engines due to spun bearing.

I believe the right step in this uncertainty situation is that people change their bearings with care and a good mechanic (that know what he is doing) minimizing the risk of fucking their engine, that is if you don't have an engine warranty.

This is the less risky situation in my opinion, but if we could determine a method to detect beforehand that the bearings are wearing too much and seizing is imminent, then we should take that approach before doing any preventive maintenance (oil test, etcetera...)

Finally, people need to chill out before typing. Paranoic text is just deviation from the truth. Nobody wants that to happen to their engine but if there is something to solve we need to breath and think. Also, BMW is to blame for this type of situations.

EDIT: Indeed there's a revision on n55 oil pump starting on 8/11. Cars from 2009-mid 2011 recieve this oil pump 11417573747 meanwhile 2/2012-now recieved 11417613549. Period between 8/11 and 2/12 was a mix between 11417573747 (an updated version it seems) and 11417613549 (not completely updated like 2/12), the reason of the upgrade is not known but should be interesting, anyways im probably going to do bearings and install an acussump afterwards, some may prefer the M2 approach. or perhaps wait and if it wrecks change for a newer n55 version

Yeah there isn't much to add to the whole rod bearing issue other than speculation at this point. I have read nearly all the threads out there and there just isn't enough documentation (pictures) to come to any real conclusion. Most of the active n55 members have moved on to newer cars, and there are tons of high mileage early n55s out there nowadays. Stay cautious and replace them if you feel like it...

I also feel the word 'spun' is used way too loosely in most threads regarding rod bearing 'issues'.

wheela · 12-27-2021, 09:33 PM

Quote:

Originally Posted by bmw335ie90

Yeah there isn't much to add to the whole rod bearing issue other than speculation at this point. I have read nearly all the threads out there and there just isn't enough documentation (pictures) to come to any real conclusion. Most of the active n55 members have moved on to newer cars, and there are tons of high mileage early n55s out there nowadays. Stay cautious and replace them if you feel like it...

I also feel the word 'spun' is used way too loosely in most threads regarding rod bearing 'issues'.

Yeah, more like siezed.

12-14-2021, 11:32 AM	#419
carguy138 Second Lieutenant 147 Rep 296 Posts Drives: E90 335i Join Date: Oct 2014 Location: NH iTrader: (0)	Anyone have any new info to share about this? I've owned my N55 335xi for 7 years and it has been perfect. Occasional track days but doing quite a few more this upcoming summer. Also looking to get a rear LSD. Just looking for any new info if anyone has any. Thank!
	Appreciate 0 Quote

12-25-2021, 12:22 PM	#420
lforter Private 23 Rep 55 Posts Drives: 135i? Join Date: May 2021 Location: CA iTrader: (0)	Is there any conclusion around this problem? Have people concluded on what's the problem? Is the rod bearing problem a prevalent one? I bought an n55 dct 2012 with 60K (prod 11/11) to repair as a proyect car (doesn't turn on with hail damage). So I'm thinking if I should replace the bearings or if it's pure paranoia going on here. I have heard that mid 2011 the oil pump and bearings were changed, but I don't know if that affects directly the rod bearing issue. Don't know what's the final verdict on this issue and would like to know if I should do this a preventative maintenance or people are getting paranoic (which is a possibility).
	Appreciate 0 Quote

12-26-2021, 01:03 AM	#423
whyzee125 Brigadier General 1992 Rep 4,014 Posts Drives: Dinan stage 2 335i Join Date: Jul 2014 Location: Chattanooga Tn iTrader: (0)	Nobody has figured it out yet. Consensus seems most of the N55 rod bearing issues happen either after hard cornering on track (almost all street cars COULD have this issue) or after OFHG replacement. Many are just fine even after OFHG, while others aren't. The majority I've seen seem go to between 70-80k miles but there are outliers on both ends. It's smart to replace your rod bearings while doing oil pan gasket or if you're past that mileage in my opinion.
	Appreciate 0 Quote

12-26-2021, 08:46 PM	#424
lforter Private 23 Rep 55 Posts Drives: 135i? Join Date: May 2021 Location: CA iTrader: (0)	A lot of speculation going on this thread, I have read all the pages and a lot of people are paranoid and aren't thinking straight due to pure anxiety I guess, nevertheless there has been good opinions, just not very organized. I agree with BBK in some notions, I don't think it's a problem inherent to 2011 n55s (even tho the spreadsheet suggest it, its data being taken on an e90 n55 forum where most if not all n55 are 2011 so there is a clear bias) However it does appear to happen to more 11 n55, I have been investigating and anecdotal experiences aren't limited to 11 but most fall in that year, so there is a point to be taken here but not conclusive as the data is too low. The n54 vs n55 debate is somewhat difficult. Meanwhile n54 is an engine prone to bearing failure, it appears that is not that prevalent as in n55s, the reason being production numbers, personal investigation (as I haven't looked deep into n54 bearing problem) or design failure is not known. The OFHG procedure does appear to be directly correlated to the bearing issue, several people that spun a bearing have done the OFHG recently. BMW boletin suggest that its related to oil pressure problems. Some cases here suggest that High Gs and oil starvation is a problem that cause bearing to spung. So, from all of that it does appears to be related with the oil system, I don't think we can pinpoint an exact problem but rather the system as a whole has its weakpoints that when exploited result in spun bearings. Some NXs engines have more weakpoints than others and this result in data having certain patterns but not conclusive ones (more 2011 than other years...). N5X engines have a probability of a sprun bearing but some iterations have a higher probability than others. How high that probability is is very hard to determine as we have too low data (there's even a possibility that people are going too paranoid about it and that the possibility is rather minimal). It's sad to say that data is too low te suggest that people should change the bearings preventively (as it could be the case), if we do then people run a risk of damaging an otherwise perfectly good engine, if we don't people run the risk of seizing their engines due to spun bearing. I believe the right step in this uncertainty situation is that people change their bearings with care and a good mechanic (that know what he is doing) minimizing the risk of fucking their engine, that is if you don't have an engine warranty. This is the less risky situation in my opinion, but if we could determine a method to detect beforehand that the bearings are wearing too much and seizing is imminent, then we should take that approach before doing any preventive maintenance (oil test, etcetera...) Finally, people need to chill out before typing. Paranoic text is just deviation from the truth. Nobody wants that to happen to their engine but if there is something to solve we need to breath and think. Also, BMW is to blame for this type of situations. EDIT: Indeed there's a revision on n55 oil pump starting on 8/11. Cars from 2009-mid 2011 recieve this oil pump 11417573747 meanwhile 2/2012-now recieved 11417613549. Period between 8/11 and 2/12 was a mix between 11417573747 (an updated version it seems) and 11417613549 (not completely updated like 2/12), the reason of the upgrade is not known but should be interesting, anyways im probably going to do bearings and install an acussump afterwards, some may prefer the M2 approach. or perhaps wait and if it wrecks change for a newer n55 version Last edited by lforter; 12-26-2021 at 10:05 PM..
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