Have you tried the M2/3/4 GTS temp sensor kit? I know bimmerworld sells it. It allows a reading for overfill and allows more oil capacity. No idea if it works on a Non M though.

AmuroRay wrote

Have you.....

I've never owned nor worked on a BMW before last year.

Almost ready to bolt down the crank!

Below is my bearing order from raceeng.com. The mains are 235°-ish groove by my measure. The rods are normal King bearings with an aftermarket coating.

This is a different block -- I was concerned about the oversize on cylinder 5. Lucky there was a good one at a local scrapper: $500 ouch.

Blue-print:
Crank runout 0.002"
Crank end play 0.004"


=-=-=-=-=-=-

CALICO COATED KING ROD BEARING: BMW N54/55(6 CYL SET) - CAL-CR222SV-STD-6

CAL-CR222SV-STD-6

$167.50

ACL RACE MAIN BEARING: BMW 3.0L N54/N55 - STD(SET-6 CYL) - 7M1397H

AC-7M1397H-STD

$271.95

Well done AbbeyRoad. I'm down here in Houston, TX. I'm a manufacturing engineer and have been tinkering with BMW's for over 10 years now, I started out with N18 motors on Mini Cooper S, then N52, then A LOT N55's, now B58. The last 5 years I was mainly building forged internals, rebuilding stock motors since I got bored from all the COVID work from home break. I've done over 30 N55 motors so far and more than half of them are EWG versions, not that it really makes too big a difference. Anyway, I just want to say that I've watched most of your Youtube postings so far and you're pretty much on point, and being extra cautious, which is great. I can't say I agree with drilling the holes out of that oil pump, but maybe your trial will lead to something new. I'll state for the record that these N55's are "temperamental" motors in my opinion. I've gone through 4 of these motors on my own X5 tuned with FBO mods and forged internals.

And just to put it out there, since I've done quite many rebuilds so far, I have the authority to say that these oil pumps may work well enough, but oil starvation IS the main cause of catastrophic rod bearing failure, almost 100% of time. The only 2 motors I come across which had rod bearing seizure were of flooded motors where water got into the motor and there's hydro-locking. And one of the hydro-locked motors has the oil pump completely ganged by water in that oil pump (Newtonian fluid). The moment I relieved that oil pump, water poured out, the crank was able to rotate freely except the #2 and #5 rod bearings were toast, I saw heat signatures on those copper-tin layers where soft babbits are completely gone, and whatever is left of the bearing shell basically welded onto the crank journal.


For all of you out there, oil starvation on an N55 is real, though millions of motors may not go through this, those who are quite seriously modded and drive with a lot of G's may realize how serious this problem gets. One may get lucky at times, but almost always, these motors CAN suck up empty space and there goes your bearing.

Another big point which was talked about by other posts here, which I agree with, is that oil service intervals need to be kept short. That whole CBS from iDrive will get you in deep shit and leave you stranded on side of the road if you're solely relying on it. I pretty much use the iDrive's oil level measurement feature when I go to a car wash, only to let the sensor read oil height. If it's not green, I'd keep it filled up to about 7-quarts total always. What I've learned from the N55's is that you need to constantly (at least once a month) check oil level, and change that oil between 3,500 to 5,000 miles. Do not wait for 10k mile or whatever that CBS says. That'll keep your oil clean and constantly checked for level.

These motors are also VERY prone to have gasket leaks. Valvecover, busted PCV (oil goes into intake tracts), front main seal, rear main seal, turbo plumbing, Oil filter housing, oil pan, etc.. These some leaks can lead to rapid oil loss where the oil sensor doesn't pick up soon enough. So you must take great care and address leaks as soon as you discover it. Good luck with Oil pan and rear main seal leaks, those will require motor to come out of the subframe and/or remove the transmission. Also with oil filter housing gasket replacement, the 3 bolts that secure the heat exchanger to the housing need to be accounted for, one of them is a shorter bolt and if you mixed up the bolt locations, you'll have one side installed loosely, and it takes less than 5 miles for oil to spew out completely and there goes your bearings again.

I've at once pieced together a kit to install the double suction S55 oil pump onto the N55, but upon mating it to my transmission is when I realized my oil pan cover was made for manual transmission. I couldn't secure it to my auto transmissions torque converter bolts that way. The only way to do this is to remove the oil pan, mate the block to the transmission first, then re-install the oil pan. But then next time if there's anything I need to do to dismantle the transmission, I'd have to undo the oil pan first in order to access the torque converter bolts. Since then I've given up the S55 pump kit and sold it. Nowadays I just learn to check oil level weekly while car pass through a carwash. Just enough time to read 100% and know what height the oil is. I noticed the harder I drive the car, the quicker the oil loss; sometimes a quart per 2k miles. That's enough to close this entire conversation if I don't check it enough and drive 5-6 thousand miles blind and half the oil's gone.



Whoever comes forth saying there aren't any oil starvation problems with an N55, clearly you either don't know what you're talking about or you're simply poorly learned and researched on these motors. I wouldn't call it a "design flaw" by BMW, but I'd be confident enough to say that by the way this motor runs, there are a few solid ways to mix up a perfect storm and toast those bearings.

And 5w-50 oils may appear a bit thick, yes, but if you know your own build and draw some intel from the way your bearing clearances are set, doing 5w-50 may be the smarter move to close the gap and keep that film intact to levitate the rods from the journals. All this misunderstanding that you must use the colored shells from BMW OEM parts are just naive. I've ran King's, ACL,s, Calico-coated, and iRox coated aftermarket bearings, and they all seemed to perform better than OEM's 2-layer crap. The coated bearings give you an extra protection when shit goes south, to an extent of how many more revs you can put it through. But OEM bearings simply will seize and weld onto the journal more than any coated aftermarket tri-layer performance bearings. So yeah, these aftermarket bearings DO perform better even during an oil starvation event; but after all, when all oil's gone and the film's lost, no bearing or coating will save your rods; except coated bearings will have you spinning a bit longer, overheat maybe, but less likely going straight for seizure and welding up to the journal.

yupetc wrote

I've at once pieced together a kit to install the double suction S55 oil pump onto the N55, but upon mating it to my transmission is when I realized my oil pan cover was made for manual transmission. I couldn't secure it to my auto transmissions torque converter bolts that way. The only way to do this is to remove the oil pan, mate the block to the transmission first, then re-install the oil pan. But then next time if there's anything I need to do to dismantle the transmission, I'd have to undo the oil pan first in order to access the torque converter bolts. Since then I've given up the S55 pump kit and sold it. Nowadays I just learn to check oil level weekly while car pass through a carwash. Just enough time to read 100% and know what height the oil is. I noticed the harder I drive the car, the quicker the oil loss; sometimes a quart per 2k miles. That's enough to close this entire conversation if I don't check it enough and drive 5-6 thousand miles blind and half the oil's gone.

I have that pan bolted up to an automatic transmission. The S series pan is the same between auto and manual. The 'auto' that pan comes with is a DCT though.

To install that pan on an automatic, Intake manifold off, starter out, crank position sensor out. Tekton 3/8" drive 18mm swivel socket. Worked great for me.

LA1Z24 wrote

I have that pan bolted up to an automatic transmission. The S series pan is the same between auto and manual. The 'auto' that pan comes with is a DCT though.

To install that pan on an automatic, Intake manifold off, starter out, crank position sensor out. Tekton 3/8" drive 18mm swivel socket. Worked great for me.

Yea that was the thought process I had at that point but I still gave up because if I ever had to deal with those bolts again with engine in the bay, my fragile spine wouldn’t last long bending and trying to get within torque in that little bitty space that’s left. And I’ve also had incidences where torquing against a locked timing plate did “bend” the flywheel at once. Result was some annoying chatter and vibration. So that’s why I didn’t go for it. But yes, the S55 oil pump with double suction is the best way to go. There are other aftermarket options available in the latter years but I didn’t want to do those because at some point if I have the sell the car as-is, I just don’t want to sweat the next owner with parts that they just can’t locate or figure out easily.

yupetc wrote

Well done AbbeyRoad. I'm down here in Houston, TX. I'm a manufacturing engineer and .......

Very interesting, thanks.

You are correct: drilling a hole in the oil pump (and/or flipping the piston) is a bad idea.

yupetc wrote

Well done AbbeyRoad. I'm down here in Houston, TX. I'm a manufacturing engineer and have been tinkering with BMW's for over 10 years now, I started out with N18 motors on Mini Cooper S, then N52, then A LOT N55's, now B58. The last 5 years I was mainly building forged internals, rebuilding stock motors since I got bored from all the COVID work from home break. I've done over 30 N55 motors so far and more than half of them are EWG versions, not that it really makes too big a difference. Anyway, I just want to say that I've watched most of your Youtube postings so far and you're pretty much on point, and being extra cautious, which is great. I can't say I agree with drilling the holes out of that oil pump, but maybe your trial will lead to something new. I'll state for the record that these N55's are "temperamental" motors in my opinion. I've gone through 4 of these motors on my own X5 tuned with FBO mods and forged internals.

And just to put it out there, since I've done quite many rebuilds so far, I have the authority to say that these oil pumps may work well enough, but oil starvation IS the main cause of catastrophic rod bearing failure, almost 100% of time. The only 2 motors I come across which had rod bearing seizure were of flooded motors where water got into the motor and there's hydro-locking. And one of the hydro-locked motors has the oil pump completely ganged by water in that oil pump (Newtonian fluid). The moment I relieved that oil pump, water poured out, the crank was able to rotate freely except the #2 and #5 rod bearings were toast, I saw [...]

So how many N55 engines have you personally seen failing on track from oil starvation? Seems like another internet forum hype.

Ilvez wrote

So how many N55 engines have you personally seen failing on track from oil starvation? Seems like another internet forum hype.

It's not a hype. I build over 10 N55 motors per year, 20% for my own and my closed circle, 80% is for side job business where I sell it through a shop which does Euro cars and does quite a few engine swaps. I deal inline 4 and 6, BMW motors only, so I can't say much about the N63's.

The ones for track use I've only done two spun rod bearing motors, and those are very well maintained vehicles; we have no other reason but to suspect oil starvation because they saw intermittent oil lamp during hard turns, and moment after, smoke in the exhaust, then speedometer dash has Christmas lights with the gift of a limp mode warning, engine shut down, finalized with a message along the lines of engine operation currently not possible, wait a while and try again. Anyways, took those motors apart and find rod bearings seized onto the crank journal. I did those rebuilds by swapping in a new crank and coated rod bearings from King/ACL.

The rebuilds I deal with outside track use are for direct replacement at a shop where they have to get another motor put in. That's where I come in. Most my N55 builds come from junkyard cores which I work with a nearby engine shop to do the boring, decking, and cleaning part of my work. A lot of the blocks I get have bearings seized onto journals, so I had to source replacement crank many times to put the motor together. I'll say, half of the motors from the shop are spun rod bearings, due to low oil stemming from neglected maintenance. It's very easy to attribute and find sources of severe oil leaks on gaskets/seals on those, which leads to low oil in the pan, thereby, "oil starvation". That's just from the shop alone. On the motor cores I get in junk yards, interesting statistics, about half of them are either spun rod bearings or flooded motors. On spun motors I can already smell it before I open up the oil pan to find it; although most times, seized crank is the first tale tell sign.

If you can't connect the dots, stay tucked and cushy on your side of the fence. You be you, bro.

yupetc wrote

It's not a hype. I build over 10 N55 motors per year, 20% for my own and my closed circle, 80% is for side job business where I sell it through a shop which does Euro cars and does quite a few engine swaps. I deal inline 4 and 6, BMW motors only, so I can't say much about the N63's.

The ones for track use I've only done two spun rod bearing motors, and those are very well maintained vehicles; we have no other reason but to suspect oil starvation because they saw intermittent oil lamp during hard turns, and moment after, smoke in the exhaust, then speedometer dash has Christmas lights with the gift of a limp mode warning, engine shut down, finalized with a message along the lines of engine operation currently not possible, wait a while and try again. Anyways, took those motors apart and find rod bearings seized onto the crank journal. I did those rebuilds by swapping in a new crank and coated rod bearings from King/ACL.

The rebuilds I deal with outside track use are for direct replacement at a shop where they have to get another motor put in. That's where I come in. Most my N55 builds come from junkyard cores which I work with a nearby engine shop to do the boring, decking, and cleaning part of my work. A lot of the blocks I get have bearings seized onto journals, so I had to source replacement crank many times to put the motor together. I'll say, half of the motors from the shop are spun rod bearings, due to low oil stemming from neglected maintenance. It's very easy to attribute and find sources of severe oil leaks on gaskets/seals on those, which leads [...]

Thanks for a very interesting info. Did I understood you correctly that the ones from track were not N55s? These do not have flashing oil lights or pressure indicators.

Neglected maintenance is not really indicator of systematic oil starvation in my books.

Ilvez wrote

Thanks for a very interesting info. Did I understood you correctly that the ones from track were not N55s? These do not have flashing oil lights or pressure indicators.

Neglected maintenance is not really indicator of systematic oil starvation in my books.

I’m strictly referring to N55’s here. So get with the program, son.

And I would urge you to wake up and change how you bookkeep because this will be the last effort I’ll even try to entertain you on the topic. Why don’t you start by neglecting your own maintenance and let that oil leak begin, get severe. Imagine you end up leaking or consuming 1-liter per thousand miles, your idrive CBS has you change oil between 9k-15k miles, you’d be long gone with emptying your oil bucket before reaching your next intervall because all you have in there are a mere 6.5-7 liters to begin with. How is that so systematically detached from causing you to have oil starvation.? Oil starvation on an N55 isn’t strictly referring to anyone deliberately cutting out the oil supply, nor does it mean the OEM lacks the wits in their design to garner this scenario but a certain few combination and flow of events will cause the oil pump to suck empty air instead of oil it needs, mind you, at all times. And when that air gap goes in between your bearing and journal, the count down begins. Low oil due to leaks, oil consumption itself, or driving on the track pulling G’s sending oil sloshing around will give the oil pump an opportunity to suck up air. That’s where rod bearings get spun on the N55’s most cases. By design, N55’s practically don’t have an oil starvation problem under good care and non-track high G use. But there are enough cases and time we spend exploring to arrive at these few causes attributing to the failed rod bearings. This can be said about any ICE where lack of oil kills the bearings due to loss of oil film between the voids.

Why puff the chest? Just trying to get some of your confusing statements straight here. N55 engines do not "flash" oil lights during track use, so do not understand what you are really saying here. You have been apparently rebuilding a bunch of N55s but only 2 from track use is what I can make of.

Been occasionally tracking my car with logs running and can confirm that oil pressure does drop during hard braking and especially into left turns. Pressure drop can be quite significant e.g. from 70-80psi to 40 but only at partial/closed throttle, lasts less than a second and pressure picks up immediately as soon as throttle is picked up. Not catastrophic drop at all and this does not trigger any warnings nor it should.

If someone chooses not to pay attention to oil level, change oil at 20+ thousand intervals, boot the engine while cold then this is not a proof of bad engine design nor systematic issue of "N55 oil starvation" but simply idiot at wheel.

yupetc wrote

I’m strictly referring to N55’s here. So get with the program, son.

Ilvez wrote

Why puff the chest? Just trying to get some of your confusing statements straight here. N55 engines do not "flash" oil lights during track use, so do not understand what you are really saying here. You have been apparently rebuilding a bunch of N55s but only 2 from track use is what I can make of.

Been occasionally tracking my car with logs running and can confirm that oil pressure does drop during hard braking and especially into left turns. Pressure drop can be quite significant e.g. from 70-80psi to 40 but only at partial/closed throttle, lasts less than a second and pressure picks up immediately as soon as throttle is picked up. Not catastrophic drop at all and this does not trigger any warnings nor it should.

If someone chooses not to pay attention to oil level, change oil at 20+ thousand intervals, boot the engine while cold then this is not a proof of bad engine design nor systematic issue of "N55 oil starvation" but simply idiot at wheel.

The idrive DOES display low oil warning if you get lucky when the oil level does run below the level sensor; many a times, this sensor don't respond that quick and don't even bother popping up the message on the idrive until it's too late. That's what I was referring to. But as I recall from that case when my friend that spun rod bearing on the track, the oil warning did come up, also the dash was displaying multiple warning lamps, which I didn't know what for, but we refer to those as the "Christmas Light" event. And last set of displayed messages were things on the idrive screen saying car's in limp mode, can't start, try back later. Anyway. it all happened very quickly and in an instant, and he did say there's white smoke behind the car for a short few seconds, too. No knocking noise, and after the car dies down, starter couldn't crank the engine at all. And you're right, I run a hobby business building N55, N20, and B-series motors, what do I know, huh? But consider the statistics, I've seen enough both from the shop that contracted me to build motors so they can have a fresh supply standing by, additionally, I have to source the motor cores from yards to begin my work. Both are channels where I get to open up the engine and try to put 2 and 2 together on what happened to it. Consider the statistics though, in sum, my work is only a miniscule attribute to the entire collective N55 or other BMW motor failures, and by the little amount of work I do where I see a spectrum of root cause to failures, I gotta say, for the most part, N20's I'll tag those as timing issue motors, N55's I tag those with maintenance neglect on oil and coolant to be the main issue (which with case of oil, spun rod bearing), plus occasional piston failures. On B48's and B58's, piston failures, and I haven't been able to pin a root cause for this; my hunch is the piston ring lands are a bit thin and detonation took the crown out. B-series motors are also notorious for milkshake in oil pan and coolant expansion tank because of the plastic oil filter housing and the failed heat exchanger gaskets. Other than that, B-series motors are solid motors.


As far as yours and my argument is concerned, I digress seeing your last paragraph, and that's exactly the point I'm making. And as long as you're aware of keeping the oil level up, yeah, we don't need this discussion anymore.

Idiots neglecting maintenance items, ignore oil leaks, and buy time when they see obvious leaks and won't spend the money to address them. These are all the beginning points of oil lowering its level which eventually lead to spun bearings. I've seen too many customers coming to my garage shop with these problems, and I could hardly punch jabs at their mentality on these maintenance items until I state "If you don't fix this, you'll end up with spun rod bearing, which leads to needing a new engine or a full rebuild". Then their eyes lit up; I even have a N55 block on the stand as a demo model.

Ilvez wrote

Why puff the chest? Just trying to get some of your confusing statements straight here. N55 engines do not "flash" oil lights during track use, so do not understand what you are really saying here. You have been apparently rebuilding a bunch of N55s but only 2 from track use is what I can make of.

Been occasionally tracking my car with logs running and can confirm that oil pressure does drop during hard braking and especially into left turns. Pressure drop can be quite significant e.g. from 70-80psi to 40 but only at partial/closed throttle, lasts less than a second and pressure picks up immediately as soon as throttle is picked up. Not catastrophic drop at all and this does not trigger any warnings nor it should.

If someone chooses not to pay attention to oil level, change oil at 20+ thousand intervals, boot the engine while cold then this is not a proof of bad engine design nor systematic issue of "N55 oil starvation" but simply idiot at wheel.

I think you've been lucky you haven't seen pressure drop below 40 on track. Depends how hard you push it. I've seen threads from guys driving their car corroborating what yupetc is saying about hitting starvation and spinning on long left hand curves. Mind you, they're pushing the car HARD, with R-compound tires at the limit of traction on the curves, so they're hitting some G's. It's physics, the oil will slosh to one side of the oil pan in those conditions, if you're on the stock oiling system nothing you can do but keep the oil level high and avoid pushing it that hard. The good news is that good maintenance, monitoring your oil level, and controlling how hard you push your car are all within your control:cool!:

FYI, you can actually log the raw oil level reading from the sensor - I've added it to my logging parameters. If people are interested, I can share how to do this for MHD on e-chassis, but I'm not familiar with f-chassis or other tuning platforms.

On the track I usually drive at the limit or bit above

To be honest F10 535i even with maxed out factory turbo tune and decent suspension is not a track platform at all, just sometimes fun to have a go. Mind due, there were no long sweeping left-handers but later when looking at logs it was certainly eye catching how oil pressure fluctuated at hard braking points and especially into left hand turns.

Actually one of our Estonian dudes who had fully track-built 135i with engine, suspension, cage and semislicks managed to brick its N55. It was a decent tune - big turbo, custom remap etc. Unfortunately he did not have logs running while engine let go and later strip-down did not fully reveal what was the root cause as one of the pistons was also disintegrated.

wheela wrote

I think you've been lucky you haven't seen pressure drop below 40 on track. Depends how hard you push it.

Ilvez wrote

On the track I usually drive at the limit or bit above

To be honest F10 535i even with maxed out factory turbo tune and decent suspension is not a track platform at all, just sometimes fun to have a go. Mind due, there were no long sweeping left-handers but later when looking at logs it was certainly eye catching how oil pressure fluctuated at hard braking points and especially into left hand turns.

Actually one of our Estonian dudes who had fully track-built 135i with engine, suspension, cage and semislicks managed to brick its N55. It was a decent tune - big turbo, custom remap etc. Unfortunately he did not have logs running while engine let go and later strip-down did not fully reveal what was the root cause as one of the pistons was also disintegrated.

I hear you about seeing those fluctuations. Since adding live oil level to my logs, it's amazing/un-nerving seeing how much it fluctuates driving around. Especially when braking; not sure where exactly the oil level sensor is, but oil definately seems to slosh away from it when slowing abruptly...

yupetc wrote

The idrive DOES display low oil warning if you get lucky when the oil level does run below the level sensor; many a times, this sensor don't respond that quick and don't even bother popping up the message on the idrive until it's too late. That's what I was referring to. But as I recall from that case when my friend that spun rod bearing on the track, the oil warning did come up, also the dash was displaying multiple warning lamps, which I didn't know what for, but we refer to those as the "Christmas Light" event. And last set of displayed messages were things on the idrive screen saying car's in limp mode, can't start, try back later. Anyway. it all happened very quickly and in an instant, and he did say there's white smoke behind the car for a short few seconds, too. No knocking noise, and after the car dies down, starter couldn't crank the engine at all. And you're right, I run a hobby business building N55, N20, and B-series motors, what do I know, huh? But consider the statistics, I've seen enough both from the shop that contracted me to build motors so they can have a fresh supply standing by, additionally, I have to source the motor cores from yards to begin my work. Both are channels where I get to open up the engine and try to put 2 and 2 together on what happened to it. Consider the statistics though, in sum, my work is only a miniscule attribute to the entire collective N55 or other BMW motor failures, and by the little amount of work I do where I see a spectrum of root cause to failures, I gotta say, for the most part, N20's I'll tag those as timing issue motors, N55's I tag those with maintenance neglect on oil and coolant to be the main issue (which with case of oil, spun rod bearing), plus occasional piston failures. On B48's and B58's, piston failures, and I haven't been able to pin a root cause for this; my hunch is the piston ring lands are a bit thin and detonation took the crown out. B-series motors are also notorious for milkshake in oil pan and coolant expansion tank because of the plastic oil filter housing and the failed heat exchanger gaskets. Other than that, B-series motors are solid motors.


As far as yours and my argument is concerned, I digress seeing your last paragraph, and that's exactly the point I'm making. And as long as you're aware of keeping the oil level up, yeah, we don't need this discussion anymore.

Idiots neglecting maintenance items, ignore oil leaks, and buy time when they see obvious leaks and won't spend the money to address them. These are all the beginning points of oil lowering its level which eventually lead to spun bearings. I've seen too many customers coming to my garage shop with these problems, and I could hardly punch jabs at their mentality on these maintenance items until I state "If you don't fix this, you'll end up with spun rod bearing, which leads to needing a new engine or a full rebuild". Then their eyes lit up; I even have a N55 block on the stand as a demo model.

Hey yupetc, anecdotally, of the spun bearing n55's you've come across, do you have a guesstimate of proportion between rwd vs. awd? On a different forum, somebody was wondering if the x-drive oil pan could help mitigate starvation from sloshing due to it's geometry acting like baffling in the oil pan. Not like such numbers would be conclusive, but I thought it was an interesting idea. Since you've seen alot of these, I'm curious what your observations have been.

wheela wrote

Hey yupetc, anecdotally, of the spun bearing n55's you've come across, do you have a guesstimate of proportion between rwd vs. awd? On a different forum, somebody was wondering if the x-drive oil pan could help mitigate starvation from sloshing due to it's geometry acting like baffling in the oil pan. Not like such numbers would be conclusive, but I thought it was an interesting idea. Since you've seen alot of these, I'm curious what your observations have been.

I am a afraid I don’t have enough data to draw conclusion on awd/rwd because I’ve seen spun bearings on both. My own X5 had spun bearing and it’s an xdrive. It’s either or at this point.

I believe there is an oiling problem with the N55 that is unrelated to maintenance or sucking air.

I don't think the feedback loop between the computer, the oil pressure sensor, and the oil pump is responsive enough. I.e. a rare sequence of driver peddle action can yield brief moments of low oil pressure at the rod bearing.

This is just my belief gathered by my understanding of how the oiling works.

yupetc wrote

I am a afraid I don’t have enough data to draw conclusion on awd/rwd because I’ve seen spun bearings on both. My own X5 had spun bearing and it’s an xdrive. It’s either or at this point.

So, assuming a car has been well maintained (oil leaks fixed as soon as they are found, oil changed every 3k- ish or yearly (whichever comes first), will continue to be maintained in the same manner, as well as monitoring live oil level via MHD, and has not, and will not be tracked, do you see any need to proactively replace rod bearings "while one is in there" replacing a leaky oil pan gasket at around 75k miles? I'm thinking probably not, but am curious to here your thoughts due to your experience level.

I just found out my oil pan is leaking and it's in the shop about to be replaced. I'm keeping the car for long haul, it's been MHD 2+ for > 3 years, and will be getting my speedtech kit installed hopefully this calendar year (but still no tracking, it's just a fun daily driver). So bearings could happen now, or in another 75k-ish miles next time the gasket starts leaking (assuming I have no issues on the current bearings, of course).

Any thoughts?

Edit: other note, I run 93 only, and have never mixed up to higher e-content, or run methanol injection. Likewise, I have no plans for ethanol or meth after install of my speedtech kit.

wheela wrote

So, assuming a car has been well maintained (oil leaks fixed as soon as they are found, oil changed every 3k- ish or yearly (whichever comes first), will continue to be maintained in the same manner, as well as monitoring live oil level via MHD, and has not, and will not be tracked, do you see any need to proactively replace rod bearings "while one is in there" replacing a leaky oil pan gasket at around 75k miles? I'm thinking probably not, but am curious to here your thoughts due to your experience level.

I just found out my oil pan is leaking and it's in the shop about to be replaced. I'm keeping the car for long haul, it's been MHD 2+ for > 3 years, and will be getting my speedtech kit installed hopefully this calendar year (but still no tracking, it's just a fun daily driver). So bearings could happen now, or in another 75k-ish miles next time the gasket starts leaking (assuming I have no issues on the current bearings, of course).

Any thoughts?

Based on your scenario, I wouldn't worry about replacing the rod bearings at all. I would just do the oil pan gasket. Make sure you check your oil level at least between every 2 months in case the oil is consumed from blow-by and maybe some ghostly PCV issues. It's a two-layer uncoated bearing, actually some pretty hard stuff, as long as oil film is present between the bearing and the journal, it'll do well.

yupetc wrote

Based on your scenario, I wouldn't worry about replacing the rod bearings at all. I would just do the oil pan gasket. Make sure you check your oil level at least between every 2 months in case the oil is consumed from blow-by and maybe some ghostly PCV issues. It's a two-layer uncoated bearing, actually some pretty hard stuff, as long as oil film is present between the bearing and the journal, it'll do well.

Thanks for your quick feedback, that's good to hear! I'll defintaley keep close eye on my oil level!