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05-31-2025LAST POST
The bearings look terrible, and I don’t blame the oil. I am glad the motor lasted 215k and hope there is no damage so it can be rebuilt.
pbonsalb wrote
The bearings look terrible, and I don’t blame the oil. I am glad the motor lasted 215k and hope there is no damage so it can be rebuilt.
Yeah, not quite so sure how those bearings are a good thing...

Here is a set of N54 bearings (running engine from wrecked car - borrowed from a post on N54Tech) with 85K miles on them from a junkyard. Questionable oil change intervals - likely followed BMW's long OCI.

This is what used bearings should like like, even at far greater mileage.

:D
Attached imageAttached image
215k miles is pretty impressive on a set of bearings in a motor like the S65.
pbonsalb wrote
The bearings look terrible, and I don’t blame the oil. I am glad the motor lasted 215k and hope there is no damage so it can be rebuilt.
I disagree. They look good.
Frozen wrote
I disagree. They look good.
Opinions are like assholes. Everyone has one.

That post does nothing to prove anything about 5W50 usage.
In fact I'd say it does more harm than good as those bearings are terrible and maybe 5w50 cause it.
tdott wrote
Frozen wrote
I disagree. They look good.
Opinions are like assholes. Everyone has one.

That post does nothing to prove anything about 5W50 usage.
In fact I'd say it does more harm than good as those bearings are terrible and maybe 5w50 cause it.
Have you ever looked at the bearing Condition thread on this very forum? Cars with 40k miles look way worse than these 215k mike bearings.

It's not a opinion it's a fact. Take those 215k mile bearings and put them next to one of the 100+ images on the bearing thread on this forum and they show less wear that 80% of them.

I agree that this is not direct proof that redline 5w30 is what helped these bearings live such a long life but it does add some credibility to Troyjeup's claim.
Frozen wrote
I agree that this is not direct proof that redline 5w30 is what helped these bearings live such a long life but it does add some credibility to Troyjeup's claim.
I disagree, there have been reports of cars making it to over 200k on stock bearings using 10w60, who is to say this wouldn't have been one of them?

Even if 5w50 was used it's entire life, it doesn't say much, just that the tolerance stack on that engine was lucky to be on the looser side.
Frozen wrote
Have you ever looked at the bearing Condition thread on this very forum? Cars with 40k miles look way worse than these 215k mike bearings.

It's not a opinion it's a fact. Take those 215k mile bearings and put them next to one of the 100+ images on the bearing thread on this forum and they show less wear that 80% of them.

I agree that this is not direct proof that redline 5w30 is what helped these bearings live such a long life but it does add some credibility to Troyjeup's claim.
Pretty much every set of S65 and S85 bearings look like garbage. Some are a little better than others. But that is just statistics at work.

Bottom line, no oil will overcome a design flaw or tolerance stack. And the bearings shown in this post are totally ruined. Same thing would have happened using Castrol 5W50, 10W60 or 0W40. Oil starvation causes wear.
Get a clue ....
Design flaw? Ahh OK ....
Yep it's flawed alright.
An engine (V8, no less) that is smooth past 8200 rpm!
I am SICK of the bashing of the #idiotengineers @BMW !
If you're stupid enough to stretch OCIs on the race bred engines in M cars you deserve worn RBs.
There, I said it

Otherwise use the best stuff on earth, Redline, and change your oil....
If you care enough

Otherwise
Have at it
At the selection in WalMart
Scharbag wrote
Frozen wrote
Have you ever looked at the bearing Condition thread on this very forum? Cars with 40k miles look way worse than these 215k mike bearings.

It's not a opinion it's a fact. Take those 215k mile bearings and put them next to one of the 100+ images on the bearing thread on this forum and they show less wear that 80% of them.

I agree that this is not direct proof that redline 5w30 is what helped these bearings live such a long life but it does add some credibility to Troyjeup's claim.
Pretty much every set of S65 and S85 bearings look like garbage. Some are a little better than others. But that is just statistics at work.

Bottom line, no oil will overcome a design flaw or tolerance stack. And the bearings shown in this post are totally ruined. Same thing would have happened using Castrol 5W50, 10W60 or 0W40. Oil starvation causes wear.
215k miles and the bearings are "totally ruined"

What an extreme statement. Thanks for the laugh man.
Frozen wrote
Scharbag wrote
Frozen wrote
Have you ever looked at the bearing Condition thread on this very forum? Cars with 40k miles look way worse than these 215k mike bearings.

It's not a opinion it's a fact. Take those 215k mile bearings and put them next to one of the 100+ images on the bearing thread on this forum and they show less wear that 80% of them.

I agree that this is not direct proof that redline 5w30 is what helped these bearings live such a long life but it does add some credibility to Troyjeup's claim.
Pretty much every set of S65 and S85 bearings look like garbage. Some are a little better than others. But that is just statistics at work.

Bottom line, no oil will overcome a design flaw or tolerance stack. And the bearings shown in this post are totally ruined. Same thing would have happened using Castrol 5W50, 10W60 or 0W40. Oil starvation causes wear.
215k miles and the bearings are "totally ruined"

What an extreme statement. Thanks for the laugh man.
Pull bearings out of a Honda at that mileage, any Honda, and report back.
330indy wrote
Get a clue ....
Design flaw? Ahh OK ....
Yep it's flawed alright.
An engine (V8, no less) that is smooth past 8200 rpm!
I am SICK of the bashing of the #idiotengineers @BMW !
If you're stupid enough to stretch OCIs on the race bred engines in M cars you deserve worn RBs.
There, I said it

Otherwise use the best stuff on earth, Redline, and change your oil....
If you care enough

Otherwise
Have at it
At the selection in WalMart
Well, explain the Audi 5.2L V10, Honda F20, Porsche GT3, Ferrari F134 etc. All of these are high revving high horsepower engines, all normally aspirated, all reliable.

The S65 is not a race engine. It produces high HP per liter, sure, but it is not a race engine. At 104hp/l, it is not really that impressive. A real race engine, such as NASCAR engines, produce ~135hp/l.

I will trust professional engine builders over random opinions.
330indy wrote
Get a clue ....
Design flaw? Ahh OK ....
Yep it's flawed alright.
An engine (V8, no less) that is smooth past 8200 rpm!
I am SICK of the bashing of the #idiotengineers @BMW !
If you're stupid enough to stretch OCIs on the race bred engines in M cars you deserve worn RBs.
There, I said it

Otherwise use the best stuff on earth, Redline, and change your oil....
If you care enough

Otherwise
Have at it
At the selection in WalMart
Those brilliant engineers at BMW were specifying 15,000 mile or once a year oil change intervals. Interestingly, the most widely accepted theory for the spun rod bearing from engine failures and the heavily worn rod bearings from preventative maintenance changes is not the oil change interval, but the bearing clearance that is much less than industry standards.
pbonsalb wrote
Those brilliant engineers at BMW were specifying 15,000 mile or once a year oil change intervals. Interestingly, the most widely accepted theory for the spun rod bearing from engine failures and the heavily worn rod bearings from preventative maintenance changes is not the oil change interval, but the bearing clearance that is much less than industry standards.
It’s unlikely the Engineers had much say in the OCI other than letting the decision makers know that it was not advised to go any further. Those decisions are usually made by people in finance in conjunction with marketing. The Engineers probably would have said they preferred a much shorter OCI.
I had to add half a quart after 4000 miles on this change of 5w50

The horror. I’m writing my congressman and I’m filing an ass claction lawsuit

My engine has 121k on it and consumes the same amount of oil it has when new. I bet if I did a leak down on it it’d be very very good as would compression and at this age it owes me nothing.. Hopefully it consumes 100% fewer bearings - i am glad I changed them. I’ve held enough rod bearings in my hands to know when something’s not right, even if I can’t identify a cause. Bmw made a great engine in the S65 no doubt, but acting like the bearings were done properly is just foolish Fanboyism. The bearings shouldn’t look like those s85 bearings, ever, no matter the mileage. The 5w50 might have bought time but the fact is BmW screwed this up, on purpose, we can speculate on motive but my belief is they were constrained by existing approved oils, accounting and free maintenance costs, and a design brief that called for getting the cars to 50k after which it would be the CPO vendor/owner’s problem at worst case for the company. They were never going to take a hit in reputation on reliability - it’s a break my wallet M car we should thank our stars it runs at all after the S38 and S14 and S62 long term problems
dparm wrote
Who is this person and why should we listen to them? Legitimate question, I have no idea who they are or their credentials.
Plus, ok ... some guy on the Internet says "oh use this..it'll solve everything in regards to bearings" - I'm pretty certain that while the bearings may be tight, BMW spent hundreds of thousands if not millions of dollars on actual research with petroleum and mechanical engineers that have specialized knowledge and skills to know precisely which kind of oil to use for the S65 and S85 engines.


I'm sticking with OEM BMW 10W-60W - I'm not going to deviate from that either. Yeah, it's way expensive but until there is empirical and axiomatic data that specifies you can deviate from what BMW recommends I won't change oil weight or brands.

Thank you,
Merlin
The “some guy on the Internet” has rebuilt about 500 S85 and S65. Maybe BMW has rebuilt more, but if they have, they have not offered any suggestions to owners on how to make the motors last longer.
CarPoor wrote
It’s unlikely the Engineers had much say in the OCI other than letting the decision makers know that it was not advised to go any further. Those decisions are usually made by people in finance in conjunction with marketing. The Engineers probably would have said they preferred a much shorter OCI.
Changing the oil every 1000 miles will not extend the life of an engine with improperly designed hydrodynamic bearings. If it is too tight, it is too tight. This not only applies to bearing to journal clearance, but also to rod side clearance. With the lack of quality control, shown by data collected by those who initially identified this issue, BMW built a bunch of really great engine with a statistical ticking time bomb.

Modern synthetics can run longer intervals. This is shown by oil analysis reports where people paid for TBN. Most people, myself included, change oil far sooner than actually required.

A quick review of Clevite's information discussing bearing failure modes will support the hypothesis that S65 and S85 bearing wear is indicative of oil starvation, not oil contamination. If viscosity were a major factor causing increased wear, everyone running 0W40 oil should be seeing much greater wear than users of 10W60. This seem to not be the case - or at least we have not seen a rash of 0W40 oil users with worn or spun bearings.

FYI:
Castrol 10W60 V@40C = 160
Castrol 10W60 V@100C = 22.7
Castrol 10W60 HTHS = 5.2

Mobil 1 0W40 V@40C = 70.8
Mobil 1 0W40 V@100C = 12.9
Mobil 1 0W40 HTHS = 3.6

Redline 5W50 V@40C = 130
Redline 5W50 V@100C = 21
Redline 5w50 HTHS = 5.0

Happy motoring.
Pull bearings out of a Honda at that mileage, any Honda, and report back.
A Honda with a V8 that revs up to 8400 RPM?
pbonsalb wrote
The “some guy on the Internet” has rebuilt about 500 S85 and S65. Maybe BMW has rebuilt more, but if they have, they have not offered any suggestions to owners on how to make the motors last longer.
This.
Frozen wrote
A Honda with a V8 that revs up to 8400 RPM?
F20C revs to 9000 RPM. 500ml per piston, same as the S65. Here is the bore and stroke:

F20C Bore = 87mm
F20C Stroke = 84mm
Mean piston speed = 25.2 m/s at 9000RPM

S65 Bore = 92mm
S65 Stroke = 75.2mm
Mean piston speed = 21 m/s at 8400RPM

The number of pistons has very little to do with rod bearing dynamics. They either work properly or they do not. I think the S65 is a wonderful engine. I own one. But BMW did not properly design the bottom end of the engine. Nor did they employ assembly techniques that ensure minimum tolerances are maintained.

This is not my opinion. This is the opinion of a group of professional engine builders. They have a very detailed thread on the subject that is full of good data that shows engine building best practices were not used by BMW. Physics is physics, regardless if it is built by the Germans.

Cheers,