[Nachos23]

Hi guys,

my MHD Stage 2+ tuned n55 is approaching 190K km (118K miles)... engine runs great and pulls strong.

been reading that rod bearings can be an issue on these engines particularly tunes ones. I know the effort involved (mine is F34 335GT).

question is?? how do i know if I need to replace them? is this a maintenance item or more of a address when XXX symptom(s) appear... I've heard people talk about rod bearing knock; but to tell if I have it?

Thanks!

If replacing; preferred brands?

[lucasborka]

It’s all about oil, keep it topped up at all times to not risk oil starvation and keep up with maintenance. 5k oil changes

There is not much problems with the N55s in F series cars. You shouldn’t worry, more problems on the earlier E series cars with N55

[cfm56d7b]

Originally Posted by Nachos23

Hi guys,

my MHD Stage 2+ tuned n55 is approaching 190K km (118K miles)... engine runs great and pulls strong.

been reading that rod bearings can be an issue on these engines particularly tunes ones. I know the effort involved (mine is F34 335GT).

question is?? how do i know if I need to replace them? is this a maintenance item or more of a address when XXX symptom(s) appear... I've heard people talk about rod bearing knock; but to tell if I have it?

Thanks!

If replacing; preferred brands?

The rod bearing wear can be identified by performing oil analysis and looking for specific metal shavings. That's what dealers when there is a concern that rod bearings may be worn.

Small percentage of N55 engines in US-spec 2013 F30 vehicles exhibited premature rod bearing wear. BMWUSA replaced these engines.

[thejeremyman9]

extensive discussion on rod bearing replacement: https://f30.bimmerpost.com/forums/sh....php?t=1893538

[johnung]

Originally Posted by Nachos23

Hi guys,

my MHD Stage 2+ tuned n55 is approaching 190K km (118K miles)... engine runs great and pulls strong.

been reading that rod bearings can be an issue on these engines particularly tunes ones. I know the effort involved (mine is F34 335GT).

question is?? how do i know if I need to replace them? is this a maintenance item or more of a address when XXX symptom(s) appear... I've heard people talk about rod bearing knock; but to tell if I have it?

Thanks!

If replacing; preferred brands?

Go on the Blackstone Labs website and order a free oil sample test kit. Send an oil sample in for analysis, about $30. That will tell you health of your bearings.

If I ever need to drop my oil pan I’ll probably replace my bearings with coated VAC bearings. They can withstand short periods without lubrication.

https://store.vacmotorsports.com/mob...s55-p4845.aspx

[Chindabest]

Hi
You wouldn’t know up until the engine started knocking.If it’s started knocking you may stop ASAP and don’t ever start or drive the car until it get fixed.
Do regular oil changes like the others said every 5000k.if there is any oil leak fix ASAP.
The only way you can tell is inspect the engine oil.you can either remove the oil sump and have a look, when you change the oil have a look or inspect the oil filter.mainly you are looking for metal particles.they are like silver metal powder in the engine oil.if you remove the oil filter and if you do a thorough check you will see them.if there is anything Like that please get the engine check than waiting and causing more damage.it will cost you more like happened to me

[Chindabest]

Originally Posted by Nachos23

Hi guys,

my MHD Stage 2+ tuned n55 is approaching 190K km (118K miles)... engine runs great and pulls strong.

been reading that rod bearings can be an issue on these engines particularly tunes ones. I know the effort involved (mine is F34 335GT).

question is?? how do i know if I need to replace them? is this a maintenance item or more of a address when XXX symptom(s) appear... I've heard people talk about rod bearing knock; but to tell if I have it?

Thanks!

If replacing; preferred brands?

For some engines it’s easier to do so.Take the oil pan out and access the bearings.If engine is already knocking stop driving asap more likely to clean the engine new oil pump and cooler also bearings

[F32Fleet]

Originally Posted by Nachos23

Hi guys,

my MHD Stage 2+ tuned n55 is approaching 190K km (118K miles)... engine runs great and pulls strong.

been reading that rod bearings can be an issue on these engines particularly tunes ones. I know the effort involved (mine is F34 335GT).

question is?? how do i know if I need to replace them? is this a maintenance item or more of a address when XXX symptom(s) appear... I've heard people talk about rod bearing knock; but to tell if I have it?

Thanks!

If replacing; preferred brands?

Google YT/Redddit vids for N55 rod knock to get an idea of what to look for..

An oil analysis can give a false negative.

When you perform an oil change look for a lot of glitter in your oil filter and in the residual oil in the oil filter housing. Google will help.