Rod bearing change?

stephenf121 · 11-28-2016, 04:51 AM

My car currently has some oil pan seepage (130k miles) so I plan on changing the gasket this year. While I have the pan down, I was wondering if anyone thinks it is a good idea to change the rod bearings while inside? I know the main cause of failures in the s62, s65 and s85 bmw motors is all rod bearing failure, and by reading our forum it seems most of our engine failures (n54) that aren't related to tuning are due to rod bearing failure as well. I have never completed a job like this, and haven't seen any DIY's on this job for the n54 so if anyone has experience doing this please chime in, or if you know of a DIY. On the s65 and s85 motors I know the rod bearings can be changed from underneath with the oil pan removed, so I assume the n54 would be similar? Let me know what you guys think.

Boland01 · 11-28-2016, 08:34 AM

If oil changes were done regularly and you have no related engine issues I would vote no. A few years back we converted our E36 328i to an M3 motor. Changed out the connecting rods as part of the process and found the rod bearing to still be well within spec. The car had 135K back then.

mxchris727 · 11-28-2016, 08:48 AM

On normal engines, rod bearings almost never wear with the exception of oil neglect.

jjbmuu · 11-28-2016, 09:05 AM

Yeah changing pistons and rods would be a better idea on these engines.

335e92tx · 11-28-2016, 09:53 AM

And rings, they have high blow-by rates.

Rod bearing failures are normally associated with low or loss of oil pressure. The bearing overheats (due to already low or limited oil flow), turns to liquid, and the clearance between the journal skyrocket and oil control (more accurately hydraulic wedge of oil) is completely lost. Next most common issue is rod fastener not being correctly torqued and the clearance is also out of spec. Most common influence of adequate oil flow and pressure are main bearings. If the mains are gone or loose replacing the rod bearings wont save you.

klipse · 11-28-2016, 11:23 AM

If you are really concerned and are planning ahead, you could get an oil analysis done and that might give you some more insight to go on.

JuniorB · 11-29-2016, 04:26 AM

+1 on doing oil analysis,of just pull one. Because leaking injectors are common,it's a good idea at your mileage to chech them,your already there. It's better to check it now,rather that waiting till you start hearing the knock,it's to late then. They don't make oversize conn rod bearings. It's a safe price of mind

11-28-2016, 04:51 AM	#1
stephenf121 Second Lieutenant 43 Rep 206 Posts Drives: 2007 335i Join Date: Oct 2015 Location: Ohio iTrader: (0)	Rod bearing change? My car currently has some oil pan seepage (130k miles) so I plan on changing the gasket this year. While I have the pan down, I was wondering if anyone thinks it is a good idea to change the rod bearings while inside? I know the main cause of failures in the s62, s65 and s85 bmw motors is all rod bearing failure, and by reading our forum it seems most of our engine failures (n54) that aren't related to tuning are due to rod bearing failure as well. I have never completed a job like this, and haven't seen any DIY's on this job for the n54 so if anyone has experience doing this please chime in, or if you know of a DIY. On the s65 and s85 motors I know the rod bearings can be changed from underneath with the oil pan removed, so I assume the n54 would be similar? Let me know what you guys think.
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11-28-2016, 08:34 AM	#2
Boland01 Lieutenant 152 Rep 460 Posts Drives: 2010 535ix, 2008, 2007 335i Join Date: Sep 2013 Location: Magnolia, TX iTrader: (0)	If oil changes were done regularly and you have no related engine issues I would vote no. A few years back we converted our E36 328i to an M3 motor. Changed out the connecting rods as part of the process and found the rod bearing to still be well within spec. The car had 135K back then.
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11-28-2016, 08:48 AM	#3
mxchris727 Captain 195 Rep 665 Posts Drives: '03 M5, '06 325i, '12 M3 Join Date: Aug 2012 Location: Westport, CT iTrader: (0)	On normal engines, rod bearings almost never wear with the exception of oil neglect. __________________ BMW GT1 (INPA, DIS, WinKFP, ect..), ISTA/P & /D is up and running! PM me if you want to stop by and code your car. Last edited by mxchris727; 11-30-2016 at 10:38 AM..
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11-28-2016, 09:05 AM	#4
jjbmuu 4ut0strd4 47 Rep 223 Posts Drives: 08 AW E92 335i 6 Speed Join Date: Nov 2011 Location: Florida iTrader: (0)	Yeah changing pistons and rods would be a better idea on these engines.
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11-28-2016, 09:53 AM	#5
335e92tx ahat 1073 Rep 2,592 Posts Drives: Was '07-335e92 - Now '13-335IS Join Date: Mar 2008 Location: Texas iTrader: (6)	And rings, they have high blow-by rates. Rod bearing failures are normally associated with low or loss of oil pressure. The bearing overheats (due to already low or limited oil flow), turns to liquid, and the clearance between the journal skyrocket and oil control (more accurately hydraulic wedge of oil) is completely lost. Next most common issue is rod fastener not being correctly torqued and the clearance is also out of spec. Most common influence of adequate oil flow and pressure are main bearings. If the mains are gone or loose replacing the rod bearings wont save you. __________________ '13 335IS N54 (1 of 373 LeMans Blue out of 3597 total production e92)- Grey interior (1 of 24 in LMB with any trans- 1 of 14 with DCT)-MODS -MFactory LSD/MHD-BQ custom Tune/ATM-IC/AFE Momentum GT Intake/Konis/Mfront&HeimJoint Rear rods&arms/Brembos. https://photos.app.goo.gl/Lo6aHZRo7XqtPkhL8
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11-28-2016, 11:23 AM	#6
klipse Banned 39 Rep 134 Posts Drives: 09 E93 335i Join Date: Nov 2016 Location: usa iTrader: (0)	If you are really concerned and are planning ahead, you could get an oil analysis done and that might give you some more insight to go on.
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11-29-2016, 04:26 AM	#7
JuniorB Major 186 Rep 1,017 Posts Drives: 07 e60 525 N54 Join Date: Mar 2016 Location: Rhode Island iTrader: (0)	+1 on doing oil analysis,of just pull one. Because leaking injectors are common,it's a good idea at your mileage to chech them,your already there. It's better to check it now,rather that waiting till you start hearing the knock,it's to late then. They don't make oversize conn rod bearings. It's a safe price of mind
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