ANOTHER rod bearing question

I haven't seen this one specifically asked yet; I did look.

I have an '11 with ~26k miles on the clock. I called EAS and they said I don't need to do it until upwards of 50k miles. However, from what I've read on here some low mileage cars occasionally do get hit with the failure.

Here's the question:
If I get the rod bearing service done now, will I need to do it again at some point in the future? If it's a one-time deal, I don't know why I'd wait. I'm keeping the car for a long time.

I changed mine to be and arp bolts at 65k. The original bearings were in perfect condition. Installer was surprised and was wondering if they were changed. They weren't to my knowledge.

I think you’re fine at that mileage. I changed mine at 85k

There are only a few instances of a second set of bearings being installed. The highest mileage that I recall was about 80k after install. This was because of damage to the oil pan. Until more owners install a second set and wear patterns are confirmed to be improved, it would seem that replacing them at some point is worthwhile. I replaced mine about 75k miles ago and am planning to replace before 100k are on them.

If the car is new to you and you don't have a clue as to how it was used or abused before your ownership, just do it and always drive your car with a measure of mechanical sympathy until the oil is fully warm. You might only have to do it once, if there is a maintenance interval for rod bearings, it isn't crystal clear yet. But practicing good driving habits and choosing bearings with a more reasonable amount of clearance should bring you many years of fun.

At this point, the rod bearing issue has been beat to absolute death, brought back to life and then beat again. You're the only one who can answer that question and the only one who has to live with whatever you decide.

without even reading any responses I'll guarantee you're gonna get an equal amount of answers supporting both sides of the argument. No one can give you a definitive reason to do or not to do the bearings at any milage because some are fine at 100k and some are trashed at 50k and the same can be said the other way around.

The only thing to ask is what you can answer yourself. What will make you more comfortable when you sleep at night?

LakeSurfer wrote

At this point, the rod bearing issue has been beat to absolute death, brought back to life and then beat again. You're the only one who can answer that question and the only one who has to live with whatever you decide.

without even reading any responses I'll guarantee you're gonna get an equal amount of answers supporting both sides of the argument. No one can give you a definitive reason to do or not to do the bearings at any milage because some are fine at 100k and some are trashed at 50k and the same can be said the other way around.

The only thing to ask is what you can answer yourself. What will make you more comfortable when you sleep at night?

This OP. You'd be the best and only fair source to your question.
Regarding for ever life on a new set of shells I'd read in on the tons of available info on the board and form your opinion. The shape of old shells and selection of new will also provide some guidance to when another round possibly is relevant.

If you're asking this question at all, even though it's been beat to death, that means you have a real concern about this potential issue. You will not get the reassurance you're looking for from an overwhelming response here telling you that you don't need do it. Hence, you'll always have this in the back of your mind. So now you're just deciding if you should do it now or in another 20 to 30k miles. If you're comfortable with letting the car get to over 50k+ miles on stock bearings with a known potential issue, then with new bearings you definitely won't need to worry about it for that many miles and some. So does it really matter that you're delaying it 20k more miles when after you've gotten it done you won't have to think about it realistically till 100k? That's way down the line. Just do it and forget it. I have a 2013 with under 30k miles and I'm going to get it done come spring time.

Battle wrote

I changed mine to be and arp bolts at 65k. The original bearings were in perfect condition. Installer was surprised and was wondering if they were changed. They weren't to my knowledge.

I also changed mine to BE bearings and BE bolts at about the same mileage, but I thought my OEM bearings came out looking awful.

Different use cases and differing manufacturing tolerance stackups may have an effect.
You just won't know (sleep well) until you invade the crankcase.

My car has always lived in a mild climate, always been garaged, always warmed up properly, over serviced.

But the car had been on the boost for 59,000 of those 65,000 miles.

Pics are of the best and worst looking OEM shell pairs…

No rod bearings are not a one time job over the lifetime of the car. Even BE can't guarantee you never need to replace their bearings (I know cos I asked).

I will do mine every 80k kms cos when I removed mine at 90k kms they were shot and showing copper. Again this is my own thoughts and endorsed/recommended by no one else. Rod bearings have become a matter of religion, so you do you. Lol

I found this pic of a rod bearings on a car with 9000 miles. Thought it was interesting.

https://www.m3post.com/forums/showthread.php?t=881588&page=9

Redd wrote

No rod bearings are not a one time job over the lifetime of the car. Even BE can't guarantee you never need to replace their bearings (I know cos I asked).

I will do mine every 80k kms cos when I removed mine at 90k kms they were shot and showing copper. Again this is my own thoughts and endorsed/recommended by no one else. Rod bearings have become a matter of religion, so you do you. Lol

Lol.

Rod bearings are not wear items if they have adequate oil flow.

But, you do you.

Scharbag wrote

Lol.

Rod bearings are not wear items if they have adequate oil flow.

But, you do you.

Totally agree with you. But that point has been moot since a couple of generations of M3s before the E9x. We play the cards we are dealt.

If you're going to do it, do it for your own sanity. There is no way we can tell you a specific mileage or frequency to change them. Statistically, failures/pre-mature wear appears to be random.

Trying not to be mean about it, but there's no point in asking this question.

I did RB at 25K on my 09 this past year. I'm the second owner and wanted the peace of mind.

Cheap insurance considering the cost of a spun bearing. If you plan on owning it for awhile, go ahead and do them. If you are one of those owners that flips cars every 3 years, not going to be worth it for you. I bought my '08 in 2019 with 58k mi and changed the RB at 63k mi. They looked "ok" in M3 standards but now with fresh BE/ARP in there, I can enjoy the car for what it is. I have no plans to ever get rid of my M3 so getting them done ASAP made sense to me.

I have a low mileage 11 and replaced them around similar mileage. I am glad I did , they where not bad for an m3, but bad enough that I am glad they are done and I don’t have to worry about them any more.

Do you have adequate oil flow?

My 2008 had 64k or so on it when I had the RB replaced a year ago. Low miles for an '08. The shop found silicone where a gasket should have been.




Pop open the oil pan and...silicone clogging the oil pick-up. Engine NEVER sounded like it was oil starved. For some reason, someone opened up the bottom, never replaced the OEM RB, and put it back together with silicone that got into the pickup. You never know what you'll find. So glad I didn't wait to do my RB.

Denny347 wrote

My 2008 had 64k or so on it when I had the RB replaced a year ago. Low miles for an '08. The shop found silicone where a gasket should have been.


Pop open the oil pan and...silicone clogging the oil pick-up. Engine NEVER sounded like it was oil starved. For some reason, someone opened up the bottom, never replaced the OEM RB, and put it back together with silicone that got into the pickup. You never know what you'll find. So glad I didn't wait to do my RB.

Wow, and the shells looked ok?

Denny347 wrote

My 2008 had 64k or so on it when I had the RB replaced a year ago. Low miles for an '08. The shop found silicone where a gasket should have been.

Wow, classic case of using WAY too much RTV! For the engines we build the spec is for a 2mm bead on any sealing surface in the oil cavity. That first pic looks like WAY more than that squeezed out the side, lol! Glad you caught that!

Helmsman wrote

Wow, and the shells looked ok?

Not bad at all for OEM RB.