S65 M3 engine

[Kitsch]

Conrod bearing issues has been well known long enough to cause distress and panic.

Oil or user problem that cause failure?

Is M twin power (shell) 10w60 the right oil?

What is the proper way to warm up this car?
- manual says need not wait but drive off slowly till oil are properly warmed.
- owners tend to wait till the temp raise to normal range

Whos right?

 

[02SE]

I have an S85 powered 6-speed manual M6. I prefer Redline 10w60 oil. I start it and drive it easy until everything is up to operating temp. It sees trips to redline every time I drive it. No issues to date.

 

[d00df00d]

to BITOG!

I just got a car with this engine, myself. Been diving into this issue as well.


Originally Posted by Kitsch
Conrod bearing issues has been well known long enough to cause distress and panic.

Oil or user problem that cause failure?

Unknown at this point.

Another hypothesis is that the clearances are too tight. Also unknown.

I suspect it's a combination of many things and not easily pinned down. Either way, it's probably best to just assume that rod bearings are a maintenance item every 60k-100k miles, and use oil analysis regularly to try to get some advance warning of excess wear.


Originally Posted by Kitsch
Is M twin power (shell) 10w60 the right oil?

It may be the only current oil that has been fully tested in this engine. It's definitely the only one BMW claims was designed for this engine. Castrol TWS used to be the only such oil; it's still around but I'm not sure if it has been reformulated since BMW dropped Castrol.


Originally Posted by Kitsch
What is the proper way to warm up this car?
- manual says need not wait but drive off slowly till oil are properly warmed.
- owners tend to wait till the temp raise to normal range

Whos right?

The manual.

 

[Gokhan]

Many people reported dramatically less wear in UOAs with 0W-40 than with 10W-60 in BMW forums. 10W-60 is probably unnecessarily thick unless you're racing and the oil gets really hot.

 

[d00df00d]

Originally Posted by Gokhan
Many people reported dramatically less wear in UOAs with 0W-40 than with 10W-60 in BMW forums.

That's hardly definitive,though.

 

[Trav]

https://www.castrol.com/en_us/unite...otor-oil/castrol-edge/edge-supercar.html

 

[oghl]

I wonder: would adding more zinc and/or moly be helpful here? If the bearing is pushing thru the oil film even with 10w60, then maybe more zinc and/or moly will reduce bearing wear.

The other question is whether replacing a catalytic converter would be less costly, since adding zddp may cause cat failure.

 

[d00df00d]

Originally Posted by oghl
I wonder: would adding more zinc and/or moly be helpful here? If the bearing is pushing thru the oil film even with 10w60, then maybe more zinc and/or moly will reduce bearing wear.

Technically yeah. It'd have to, right? The question is how much. One of the few things I know about this stuff is that when there's a design flaw, or a mismatch between design and usage, lubricant choice almost never makes more than a small difference. You can always pick a wrong lubricant and make the problem worse, but it's extremely unlikely that you can find a lubricant that makes things noticeably better.


Originally Posted by oghl
The other question is whether replacing a catalytic converter would be less costly, since adding zddp may cause cat failure.

The OE cat section is a lot more expensive than rod bearing replacement, but there are cheaper aftermarket options.

 

[splinter]

Notwithstanding its electronically variable rev limit, how frequently do you spin it up past 8000?

 

[Gokhan]

Originally Posted by d00df00d
Originally Posted by Gokhan
Many people reported dramatically less wear in UOAs with 0W-40 than with 10W-60 in BMW forums.
That's hardly definitive,though.

If I had one of these S65 engines with the improper bearing geometry (Was it too tight thrust clearance?), I would stay away from 10W-60 and use 0W-40 or thinner, as the wear and failure was caused by oil starvation because of the too tight clearance. Otherwise, 10W-60 is fine and you can push that oil to extreme-temperature limits without thinning too much.

 

[Brigadier]

Originally Posted by oghl
I wonder: would adding more zinc and/or moly be helpful here? If the bearing is pushing thru the oil film even with 10w60, then maybe more zinc and/or moly will reduce bearing wear.

The other question is whether replacing a catalytic converter would be less costly, since adding zddp may cause cat failure.


Or something like the Hy-Per Lube ZRA.

 

[edyvw]

Originally Posted by Gokhan
Originally Posted by d00df00d
Originally Posted by Gokhan
Many people reported dramatically less wear in UOAs with 0W-40 than with 10W-60 in BMW forums.
That's hardly definitive,though.

If I had one of these S65 engines with the improper bearing geometry (Was it too tight thrust clearance?), I would stay away from 10W-60 and use 0W-40 or thinner, as the wear and failure was caused by oil starvation because of the too tight clearance. Otherwise, 10W-60 is fine and you can push that oil to extreme-temperature limits without thinning too much.

What is thinner than 0W, I am very interested in hearing that?

 

[Gokhan]

Originally Posted by edyvw
Originally Posted by Gokhan
Originally Posted by d00df00d
Originally Posted by Gokhan
Many people reported dramatically less wear in UOAs with 0W-40 than with 10W-60 in BMW forums.
That's hardly definitive,though.
If I had one of these S65 engines with the improper bearing geometry (Was it too tight thrust clearance?), I would stay away from 10W-60 and use 0W-40 or thinner, as the wear and failure was caused by oil starvation because of the too tight clearance. Otherwise, 10W-60 is fine and you can push that oil to extreme-temperature limits without thinning too much.
What is thinner than 0W, I am very interested in hearing that?

By thin or thick, I'm strictly referring to the HTHSV in this context, which is the viscosity that matters for the bearings.

 

[d00df00d]

Originally Posted by Gokhan
Originally Posted by d00df00d
Originally Posted by Gokhan
Many people reported dramatically less wear in UOAs with 0W-40 than with 10W-60 in BMW forums.
That's hardly definitive,though.

If I had one of these S65 engines with the improper bearing geometry (Was it too tight thrust clearance?), I would stay away from 10W-60 and use 0W-40 or thinner, as the wear and failure was caused by oil starvation because of the too tight clearance. Otherwise, 10W-60 is fine and you can push that oil to extreme-temperature limits without thinning too much.

Again, it's not yet clear whether the clearance is the issue. Bearings with more clearance haven't yet been shown to last longer, and there are other hypotheses that have not yet been ruled out.

 

[oghl]

Or just rev it 1k rpm below maximum

 

[d00df00d]

I drive like a granny until the oil is up to temp. No more than half throttle and half the indicated redline until the fluid is well past the first dot on the temp gauge.

 

[Gokhan]

Originally Posted by d00df00d
Again, it's not yet clear whether the clearance is the issue. Bearings with more clearance haven't yet been shown to last longer, and there are other hypotheses that have not yet been ruled out.

Even more reason not to use the recommended 10W-60.

Originally Posted by d00df00d
I drive like a granny until the oil is up to temp. No more than half throttle and half the indicated redline until the fluid is well past the first dot on the temp gauge.

Or dump the granny 10W-60 oil and replace it with a yuppie 5W-30 or 0W-30 oil (still with HTHSV >= 3.5 cP) and drive normally. This said, even with TGMO 0W-20, I don't go hard on the throttle until the engine reaches the normal operating temperature.

BMW specifies both 5W-30 and and 10W-60 for M engines, doesn't it?

 

[d00df00d]

For this particular engine, BMW specs one oil, and one oil only. That oil used to be Castrol TWS 10W-60, and now it's BMW Twin Power Turbo 10W-60. They say other oils (LL-01 or at least ACEA A3, ideally thicker grades) can be used in a pinch but only for top-off, and that if you do that, you should drain and refill with the spec oil ASAP.

Regarding the rest, I'm not sure if you're misreading or just reasoning in a way I don't understand. What is the path from "we don't know whether clearances are the problem" to "you should run a thinner oil?"

 

[Gokhan]

Originally Posted by d00df00d
For this particular engine, BMW specs one oil, and one oil only. That oil used to be Castrol TWS 10W-60, and now it's BMW Twin Power Turbo 10W-60. They say other oils (LL-01 or at least ACEA A3, ideally thicker grades) can be used in a pinch but only for top-off, and that if you do that, you should drain and refill with the spec oil ASAP.

Regarding the rest, I'm not sure if you're misreading or just reasoning in a way I don't understand. What is the path from "we don't know whether clearances are the problem" to "you should run a thinner oil?"

I saw this:

https://www.m3post.com/forums/showthread.php?s=3e027018ad08d7c2b7f5877faf45ed39&t=897730

The reasoning is that the if the recommended oil isn't working, you may experiment with a different oil.

 

[d00df00d]

Originally Posted by Gokhan
I saw this:

https://www.m3post.com/forums/showthread.php?s=3e027018ad08d7c2b7f5877faf45ed39&t=897730

Great. Did you read it?

The link to the page on BMW's site is 404ing, and Archive.org doesn't seem to have a copy more recent than 2012. But in 2012, it basically said exactly what I spelled out in this thread. Screencaps below.

So... Thanks, I guess. :]


Originally Posted by Gokhan
The reasoning is that the if the recommended oil isn't working, you may experiment with another oil.

Still don't know what you mean.

Could we paraphrase this as "the engine is failing with the spec oil, therefore we should feel free to use a different oil"?