0W-40 and Potential Rod Bearing Wear....0W-50 on the Street?

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3
Location
TX
BMW high performance engines have had a near 20 year record of having rod bearing issues. In the pursuit of HP and minimizing internal friction, they have narrowed the bearing from the legacy rod bearing that didn't have any issues. There were also come clearance issues for a period form 2003-2013. This combined with the fact that the HP/cylinder continues to climb makes me nervous on my current engine, the S55 (M3/M4). The did increase the bearing width over the last two generations, but still isn't as wide as the older bearings. The factory oil recommended is a 0W-40, and I'm currently running the Castrol Edge 0W-40 A3/B4 oil.

I've seen a hand full of posts were rod bearings were already replaced at 30,000-60,000 miles with a lot higher wear that I would expect. I'm running this because during my initial research, this looked like it had a higher percent of group IV oil, where Mobil 1 0W-40 FS was group III. Not 100% sure since all of this is hard to pin down. My first oil analysis got lost, and I'm due for an oil change. I drive the car EXTREMELY hard, and eventually plan to modify it running E85 adding 150+ hp over the stock output.

I saw Mobil's 0W-50 racing oil and it has me thinking. Anyone on here run Mobil 0W-50 on a newer vehicle on the street? I'd like the higher film strength of the 50 weight, but that comes with extreme levels of zinc and phosphorus. Can Mobil 1's oil has generally said it is safe to run and blend with other oils. Thoughts on substituting a quart or two of the 0W-50 in the next oil change if I switch to Mobil 1 0W-40 FS? Any other oils I need to be considering? I run 15W-50 in my older turbo BMW, but concerned with the large difference in the 0W vs 15W, but would like the little extra zinc and phosphorus that it comes with.

Let me know your thoughts, thanks.
 
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1,884
Location
Caldwell Idaho
I doubt a wide viscosity spread oil will give you the "film strength" the numbers show. I can't guess a band aid for a poorly designed engine will be oil but others may chime in. Do the BMW specific boards give and advice?
 
Messages
61
BMW high performance engines have had a near 20 year record of having rod bearing issues. In the pursuit of HP and minimizing internal friction, they have narrowed the bearing from the legacy rod bearing that didn't have any issues. There were also come clearance issues for a period form 2003-2013. This combined with the fact that the HP/cylinder continues to climb makes me nervous on my current engine, the S55 (M3/M4). The did increase the bearing width over the last two generations, but still isn't as wide as the older bearings. The factory oil recommended is a 0W-40, and I'm currently running the Castrol Edge 0W-40 A3/B4 oil.

I've seen a hand full of posts were rod bearings were already replaced at 30,000-60,000 miles with a lot higher wear that I would expect. I'm running this because during my initial research, this looked like it had a higher percent of group IV oil, where Mobil 1 0W-40 FS was group III. Not 100% sure since all of this is hard to pin down. My first oil analysis got lost, and I'm due for an oil change. I drive the car EXTREMELY hard, and eventually plan to modify it running E85 adding 150+ hp over the stock output.

I saw Mobil's 0W-50 racing oil and it has me thinking. Anyone on here run Mobil 0W-50 on a newer vehicle on the street? I'd like the higher film strength of the 50 weight, but that comes with extreme levels of zinc and phosphorus. Can Mobil 1's oil has generally said it is safe to run and blend with other oils. Thoughts on substituting a quart or two of the 0W-50 in the next oil change if I switch to Mobil 1 0W-40 FS? Any other oils I need to be considering? I run 15W-50 in my older turbo BMW, but concerned with the large difference in the 0W vs 15W, but would like the little extra zinc and phosphorus that it comes with.

Let me know your thoughts, thanks.
well first of all don't follow the long oil change interval, BMW tried 15 thousand mile intervals and pulled it back to 10 thousand miles after warranty claims from failed engines.

Have you considered a 10w60? This was recommended for the M series engines and is SN approved.

 

OVERKILL

$100 Site Donor 2021
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45,303
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Ontario, Canada
well first of all don't follow the long oil change interval, BMW tried 15 thousand mile intervals and pulled it back to 10 thousand miles after warranty claims from failed engines.

Have you considered a 10w60? This was recommended for the M series engines and is SN approved.


The 10w-60 didn't prevent the rod bearing wear or failures either, FWIW.
 
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1,119
Location
Vancouver
It is my opinion on these cars you pretty much have to budget in a bearing replacement every 60-80k or so. Costs a few grand but the good news is there are a lot of shops getting very good at it. If very good quality 0w40's aren't helping, nothing else will help much either. I certainly don't believe going to 50 grade will help and may even make it worse.
 
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1,170
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NC
Seems like back in the BMW V10 days (different engine I know, but still relatable, as it experienced similar issues) many people who ran the recommended 10w60 were experiencing more bearing failures than those who switched to 0W40 and 5W40. I'd personally run 15W50 summer/track and 0W40 winter/daily.

Mobil1 10W-60
Flash Point : 234
Hi-Temp Hi-Shear Viscosity @ 150 C: 5.7
Kinematic Viscosity @ 100 C: 22.7
Kinematic Viscosity @ 40 C: 152.7
Total Base Number: 11.8
Viscosity Index: 178

Mobil1 15W50
Flash Point : 232
Hi-Temp Hi-Shear Viscosity @ 150 C: 4.5
Kinematic Viscosity @ 100 C: 18
Kinematic Viscosity @ 40 C: 125
Total Base Number: 9.98
Viscosity Index: 160

Mobil1 0W40
Flash Point : 226
Hi-Temp Hi-Shear Viscosity @ 150 C: 3.6
Kinematic Viscosity @ 100 C: 12.9
Kinematic Viscosity @ 40 C: 70.8
Total Base Number: 12.6
Viscosity Index: 186
 

OVERKILL

$100 Site Donor 2021
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45,303
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Seems like back in the BMW V10 days (different engine I know, but still relatable, as it experienced similar issues) many people who ran the recommended 10w60 were experiencing more bearing failures than those who switched to 0W40 and 5W40. I'd personally run 15W50 summer/track and 0W40 winter/daily.

Mobil1 10W-60
Flash Point : 234
Hi-Temp Hi-Shear Viscosity @ 150 C: 5.7
Kinematic Viscosity @ 100 C: 22.7
Kinematic Viscosity @ 40 C: 152.7
Total Base Number: 11.8
Viscosity Index: 178

Mobil1 15W50
Flash Point : 232
Hi-Temp Hi-Shear Viscosity @ 150 C: 4.5
Kinematic Viscosity @ 100 C: 18
Kinematic Viscosity @ 40 C: 125
Total Base Number: 9.98
Viscosity Index: 160

Mobil1 0W40
Flash Point : 226
Hi-Temp Hi-Shear Viscosity @ 150 C: 3.6
Kinematic Viscosity @ 100 C: 12.9
Kinematic Viscosity @ 40 C: 70.8
Total Base Number: 12.6
Viscosity Index: 186

I recall similar. The guy with the highest mileage E39 M5 with stock rod bearings on M5board when I was active there was running M1 0w-40 IIRC.
 
Messages
11,663
Location
Colorado Springs
Hmmm, since when S55 has rod bearing issues?
Rod bearing issue was specific to crtain engines, and those were spinning far higher than S55 does. Even those, not all years are affected.
First of, under no circumstances use Mobil 1 0W50 racing in regular driving mode. You can use it on track, but two SERIOUS issues pop out in street use:
1. ZDDP level is way to high where it could do some premature damage to cat.
2. It does not have pretty much any detergent/dispersant capabilities as it is not made for that application.
That oil should be used on track, and changed every 500 to 1,000 miles max.

Going too high in viscosity in S55 can create actually some issues as that engine can use LL01FE with HTHS 3.0. So, stay in W40 grade.
Check Motul X-Cess GEN2 with HTHS 3.8 and 13.5cst. Seems like really robust package and has LL01 approval.
If you are not chasing approvals, Castrol Edge 0W40 has HTHS of 3.7. You can always go Redline 0W40 HTHS 4, or 5W40 HTHS 4.4.
If you still chasing some race/street oil Motul Sport 5W40 is good option (HTHS 4, 13.5cst).

Edit:
In TX, you can use 15W50 no problem. Question: Why? Thicker oil means more resistance, means loss of power, means more heat. If it is not necessary, why?

Do not mix oils to achieve some frankblend. You have no idea how it is going to work. Find appropriate oil that fits you needs.
 
Last edited:
Messages
11,663
Location
Colorado Springs
Seems like back in the BMW V10 days (different engine I know, but still relatable, as it experienced similar issues) many people who ran the recommended 10w60 were experiencing more bearing failures than those who switched to 0W40 and 5W40. I'd personally run 15W50 summer/track and 0W40 winter/daily.

Mobil1 10W-60
Flash Point : 234
Hi-Temp Hi-Shear Viscosity @ 150 C: 5.7
Kinematic Viscosity @ 100 C: 22.7
Kinematic Viscosity @ 40 C: 152.7
Total Base Number: 11.8
Viscosity Index: 178

Mobil1 15W50
Flash Point : 232
Hi-Temp Hi-Shear Viscosity @ 150 C: 4.5
Kinematic Viscosity @ 100 C: 18
Kinematic Viscosity @ 40 C: 125
Total Base Number: 9.98
Viscosity Index: 160

Mobil1 0W40
Flash Point : 226
Hi-Temp Hi-Shear Viscosity @ 150 C: 3.6
Kinematic Viscosity @ 100 C: 12.9
Kinematic Viscosity @ 40 C: 70.8
Total Base Number: 12.6
Viscosity Index: 186
Bcs. they pushed too hard before oil reached operating temperature which was absolute imperative using 10W60.
Redline claims that their 5W40 or 15W50 showed much better results in those engines than 10W60.
 

moparmuscl

Thread starter
Messages
3
Location
TX
well first of all don't follow the long oil change interval, BMW tried 15 thousand mile intervals and pulled it back to 10 thousand miles after warranty claims from failed engines.

Have you considered a 10w60? This was recommended for the M series engines and is SN approved.


No. I'm not a fan of BMW oils. Oil analysis on my wife's X5 diesel showed that the BMW oil is not great. Switched to a non-synthetic and have seen much better wear. I don't follow their excessive intervals either. 3k on the '17 M3, 6k on the X5 diesel with conventional, and 3k on the '98 turbo M3.


Seems like back in the BMW V10 days (different engine I know, but still relatable, as it experienced similar issues) many people who ran the recommended 10w60 were experiencing more bearing failures than those who switched to 0W40 and 5W40. I'd personally run 15W50 summer/track and 0W40 winter/daily.

Mobil1 10W-60
Flash Point : 234
Hi-Temp Hi-Shear Viscosity @ 150 C: 5.7
Kinematic Viscosity @ 100 C: 22.7
Kinematic Viscosity @ 40 C: 152.7
Total Base Number: 11.8
Viscosity Index: 178

Mobil1 15W50
Flash Point : 232
Hi-Temp Hi-Shear Viscosity @ 150 C: 4.5
Kinematic Viscosity @ 100 C: 18
Kinematic Viscosity @ 40 C: 125
Total Base Number: 9.98
Viscosity Index: 160

Mobil1 0W40
Flash Point : 226
Hi-Temp Hi-Shear Viscosity @ 150 C: 3.6
Kinematic Viscosity @ 100 C: 12.9
Kinematic Viscosity @ 40 C: 70.8
Total Base Number: 12.6
Viscosity Index: 186


Yeah, the heavier 60 reduced the oil flow to the rod bearings. The main problem with the S54/S65/S85 was too tight of clearances. Thicker oil didn't help any as it reduced the flow and the bearings ran hotter. I'm tempted by the 15W-50. It has worked extremely well in my '98 M3.



Hmmm, since when S55 has rod bearing issues?
Rod bearing issue was specific to crtain engines, and those were spinning far higher than S55 does. Even those, not all years are affected.
First of, under no circumstances use Mobil 1 0W50 racing in regular driving mode. You can use it on track, but two SERIOUS issues pop out in street use:
1. ZDDP level is way to high where it could do some premature damage to cat.
2. It does not have pretty much any detergent/dispersant capabilities as it is not made for that application.
That oil should be used on track, and changed every 500 to 1,000 miles max.

Going too high in viscosity in S55 can create actually some issues as that engine can use LL01FE with HTHS 3.0. So, stay in W40 grade.
Check Motul X-Cess GEN2 with HTHS 3.8 and 13.5cst. Seems like really robust package and has LL01 approval.
If you are not chasing approvals, Castrol Edge 0W40 has HTHS of 3.7. You can always go Redline 0W40 HTHS 4, or 5W40 HTHS 4.4.
If you still chasing some race/street oil Motul Sport 5W40 is good option (HTHS 4, 13.5cst).

Edit:
In TX, you can use 15W50 no problem. Question: Why? Thicker oil means more resistance, means loss of power, means more heat. If it is not necessary, why?

Do not mix oils to achieve some frankblend. You have no idea how it is going to work. Find appropriate oil that fits you needs.

S55's don't have catastrophic issues, but they aren't 100k mile engines when tuned either from what it looks like. Good call on the lack of detergents in the M1 0W-50.

I like the Motul X-Cess Gen 2 5W-40 option...never heard of it. I'm now looking at the 300W 5W-40. Seems like a great option as well. Always been a fan of Motul and ran it in my ZX-10R for year, but just forgot about it since I haven't rode in several years. Good input, thanks!
 
Messages
11,663
Location
Colorado Springs
No. I'm not a fan of BMW oils. Oil analysis on my wife's X5 diesel showed that the BMW oil is not great. Switched to a non-synthetic and have seen much better wear. I don't follow their excessive intervals either. 3k on the '17 M3, 6k on the X5 diesel with conventional, and 3k on the '98 turbo M3.





Yeah, the heavier 60 reduced the oil flow to the rod bearings. The main problem with the S54/S65/S85 was too tight of clearances. Thicker oil didn't help any as it reduced the flow and the bearings ran hotter. I'm tempted by the 15W-50. It has worked extremely well in my '98 M3.





S55's don't have catastrophic issues, but they aren't 100k mile engines when tuned either from what it looks like. Good call on the lack of detergents in the M1 0W-50.

I like the Motul X-Cess Gen 2 5W-40 option...never heard of it. I'm now looking at the 300W 5W-40. Seems like a great option as well. Always been a fan of Motul and ran it in my ZX-10R for year, but just forgot about it since I haven't rode in several years. Good input, thanks!
300V is same as Mobil1 0W50. It lacks detergents and dispersants.
I am not sure that S55 is not 100k engine if tuned. BMW changed block from N55 to allow more power and ability to tune. Is it as sturdy as B58? No, that engine is made in mind for some ridiculous tuning numbers.
The way your preferences are, this is what I think your best choices are:
Redline 5W30, 5W40 or 0W40 (Bimmerworld recommends Redline 15W50for track, Redline Oil Company disagrees with that).
Motul Sport 5W40
Motul X-Cess 5W40 GEN2
Mobil1 15W50
Mobil1 5W50
Castrol 5W50
 
Messages
4,575
Location
Decatur AL USA
I have no dog in this fight (read I'm not a BMW Owner so its up to you if you wish to ignore) but the thing with Redline is they are often not really the same viscosity as typical oils. Oils should really be selected based on HTHS instead of SAE Viscosity.

The right oil really depends on your average oil temps. 0W-16 would be better on a cold start even in midsummer. 70 Grade might be better if you truly have undersize bearings at 130C+ (266F) Sump Temps on the Track. You need to look at the bearing size, torque load, rpm and oil temp to decide what the ideal HTHS is for your application.

How I would do it:
Street Detergent Package
Minimum HTHS Required
Thinnest SAE Viscosity
Best cold rating

Select your candidates based on that criteria and then decide the one that you prefer.

The oil I run in my 3 bhp per liter drag engine on the strip is not the same oil I would run on the track because you would have a 100F difference in sump temps.
 
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Messages
520
Location
South Wales, UK
Drop the winter grade. Look at Shell Rotella T6 15w40 or even Mobil Delvac Extreme 15w40.

They have next to no VII to shear and will be far more robust with great TBN starting points and depletion rates.
 
Messages
49
Location
Gulf Coast
Put in oil that meets specifications. Use an OCI of 3-5k and do an oil analysts every oil change. Oil won’t fix under sized bearings. The UOA will let you find impending bearing fail and you’ll spend about the same money.
 
Messages
11,663
Location
Colorado Springs
Is there something we can't see with a simple voa/uoa (genuine question)? They both seem to have a decent amount of calcium/magnesium if not both. Granted, less than other oils.
I would fallow what Motul says, and Motul is saying use it strictly on street due to chemical composition.
One thing about these oils is that they do oxidize fast due to amount of Esters. They have natural acidity, but probably lacking oxidization control in order to achieve intended purpose on track.
 
Messages
11,663
Location
Colorado Springs
What did BMW do wrong to cause rod bearing to fail? Too narrow? Too small of a journal?
I think journal was small and it was on engines spinning 9,000rpms. Then they tried to resolve it with 10W60 oil, but bcs. of thickness, it had same issue as most drivers did not pay attention on proper oil temperature, pushing it hard when cold.
Redline is focused on BMW very specifically, and they claim that their 5W40 oils are working perfectly in those engines and according to them, do not have issues. Could be marketing, but who knows.
New M engines do not have that issue as they do not spin that high due to turbo.
 
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