Choosing correct viscosity for BMW M5 w/ S63TU 4.4L V8

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Long time lurker, first time poster here. I've gone WAY down the rabbit hole and feel like I can't find a solution in the maze of information I've uncovered, so I'm hoping to get some insights from others here. I'll try and be as clear as possible with my situation and my questions.

The car in question is an unmodified 2015 BMW M5 (F10). It's located in SE England, so the climate is relatively mild with no extreme heat or cold. The car is garaged and not a daily driver; it covers about 2,000 miles per year at best. Due to being garaged, it is not typically started in below freezing conditions. The car is used for longer journeys and some spirited driving, but is not tracked. I do not need to top off the oil between changes, which is actually quite rare for the S63 engine, as burning through a liter is not unusual. I will change the oil annually regardless of mileage.

Overarching Concern: The engine is widely known to eat con rod bearings and grenade, so having too thick of an oil could exacerbate this issue at start up. However, the engine can also can run very hot, so having a thinner oil to protect rod bearings at cold start may not be sufficient to protect the engine at higher temps.

The owner's manual recommends either 0W-30 or 0W-40. However, these viscosity levels have different properties, so this is not actually helpful, IMO. If you go to a dealership in the UK, they will fill it with 0W-30. In the US, BMW LL-01 spec is used, while in Europe LL-04 is used due to the lower sulfer content in our fuel. Many M5 guys seem to use a 5W-40 weight oil, or even thicker, with the rationale that the S63TU runs very hot and needs something thicker than a 0W-30 for proper protection. This leads me to my first few questions:

Question 1: If the fuel available is low sulfer, is it better to run a lower SAPS oil (like the LL-04 spec)? I know lower SAPS is better for the emissions system, but this aside, does a higher SAPS oil provide better engine protection? It seems that most 5W-40 oils are higher SAPS, so if I run this viscosity then it will be with a LL-01 spec. I've also read that with direct injected engines, a lower SAPS oil can help reduce carbon build up on the valves, but I'm not sure how much truth there is to this.

In my last oil change, I decided to increase the oil viscostiy a bit from 0W-30 to 5W-30, choosing to use Ravenol VMP. With all this new research I've done, I'm now wondering if I should be increasing viscosity yet again. Where I get hung up is when I start comparing the mm²/s figures for viscosity at 40C and 100C. The Ravenol VMP 5W-30 is 66.3 and 11.9, respectively. If I stay with Ravenol and look at their VST 5W-40, the figures are 79.4 and 13.5.

Question 2: In cold start conditions, is there a material difference in how the oil would behave (or how quickly it would lubricate rod bearings) when looking at the 5W-30 and 5W-40 figures above (66.3 vs 79.4)? Similarly, at hot temps, is there a material difference in how they would protect the engine (11.9 vs 13.5)?

Thank you in advance for any guidance you are willing to share.
 
The things you’re asking about (winter rating, etc.) are irrelevant here. Use a winter rating that’s appropriate for your starting temperature. Above -30 or so an oil with a 5W rating is acceptable. Below that use one with a 0W rating.

Go by the approval. An oil with a Longlife-04 approval is fine. Any oil with that approval essentially renders the grade irrelevant as the approval dictates a minimum HT/HS. The rest of what you’re hung up on is mostly noise.

Design and material defects are hard to correct with an oil.
 
Good on ya for coming out of the shadows. Now the fun begins.

Couple things I would look for in your application. Primarily, HTHS, secondary, SAPS, tertiary, viscosity (within range). Not familiar with offerings across the pond, but the Ravenol you are using is pretty good from what I hear. Do you know what your oil temps run? Truthfully, 2K you could use most anything that meets LL spec and be quite fine. And especially with how you drive it, viscosity is even more of moot point. Don't worry about SAPS and deposits, the car will probably be long gone before you have to worry about those. No definitive evidence on how much (if any) SAPS will contribute to them in a DI engine IMHO anyway. If you're happy with the VMP, motor on and enjoy the car.
 
Q1: LL01 oils have greater buffering capacity for fuels which are higher in sulphur. Sulphur was lowered so DPF/OPF could be used to clean emissions. For all intensive purposes LL01 and LL04 have the same performance requirements so can use either obviously. Intake deposits haven't been a thing with BMW DI petrol engines for over 15 yrs and ran LL01 and later LL01fe in the US. Valves at 100k miles exhibit nominal buildup.

Q2: No difference in your climate. The biggest difference will be in HTHS. The 40 grades will be around 3.7 or higher and the 30 grades will be between 3.5-3.7. (Assuming LL01 or LL04).

Your engine just runs hot so you want avoid that 2 yr / 24k miles interval I've read about in the UK. Maybe change lesser of 1 yr or 5k miles and keep it stock.

The S63 is a crazy piece of engineering. GL and have fun with the car.
 
Wow, thank you all for the very prompt replies!

Couple things I would look for in your application. Primarily, HTHS, secondary, SAPS, tertiary, viscosity (within range). Not familiar with offerings across the pond, but the Ravenol you are using is pretty good from what I hear. Do you know what your oil temps run?
Regarding engine temps, the F10 M5 thankfully has oil temp on the dash (instead of coolant temp). I know this will sound odd, but when I first got the car and it had 0W-30 in it, it seemed to run a bit cooler than when I changed to the 5W-30 Ravenol. With the former it sat dead on the 95C mark, while with the latter it will sit just a bit above, so probably around 100-105C. The marks are in 25C increments, so it's hard to be precise. I could also just be completely nuts about the different oil temps, but I swear I cannot recall the car ever going above the 95C mark until Ravenol went in.

I've also been comparing the HTHS and SAPS figures for all these oil options as well, and based on some other comments, it sounds like these may be more important than the viscosity measures at cold/hot. Do you have a view on lower vs higher SAPS would be better in this application?

The things you’re asking about (winter rating, etc.) are irrelevant here. Use a winter rating that’s appropriate for your starting temperature. Above -30 or so an oil with a 5W rating is acceptable. Below that use one with a 0W rating.

Go by the approval. An oil with a Longlife-04 approval is fine. Any oil with that approval essentially renders the grade irrelevant as the approval dictates a minimum HT/HS. The rest of what you’re hung up on is mostly noise.

Design and material defects are hard to correct with an oil.
It had crossed my mind that a lot of this data is just "noise," so it's actually nice to hear that I may be creating a problem where one does not exist. I can assure you I will never start the car anywhere near a temp of -30. Even if it's close to freezing the car isn't coming out, as the tires are not going to have the ability to manage the car's power. The F10 is still rear wheel drive only (either fortunately or unfortunately, depending on how you look at it!).

Ultimately, I know the rod bearings are a maintenance item on the S63 :rolleyes:, so I'm not trying to find an oil that will fix this issue. I just want to make sure I'm not prematurely accelerating the problem with a factor that I have control of (i.e. the type of oil).

Q1: LL01 oils have greater buffering capacity for fuels which are higher in sulphur. Sulphur was lowered so DPF/OPF could be used to clean emissions. For all intensive purposes LL01 and LL04 have the same performance requirements so can use either obviously. Intake deposits haven't been a thing with BMW DI petrol engines for over 15 yrs and ran LL01 and later LL01fe in the US. Valves at 100k miles exhibit nominal buildup.

Q2: No difference in your climate. The biggest difference will be in HTHS. The 40 grades will be around 3.7 or higher and the 30 grades will be between 3.5-3.7. (Assuming LL01 or LL04).

Your engine just runs hot so you want avoid that 2 yr / 24k miles interval I've read about in the UK. Maybe change lesser of 1 yr or 5k miles and keep it stock.

The S63 is a crazy piece of engineering. GL and have fun with the car.
If either LL-01 or LL-04 are truly interchangeable, is there any measurable pro/con between them in this application? Again, I read somewhere that a higher SAPS content can provide better overall engine protection (but maybe my frequent oil changes negate this benefit of a higher SAPS oil). Maybe focusing on metrics like the lowest NOACK and highest HTHS may be more beneficial?

I'm not sure what BMW recommends for oil intervals in the UK, but I certainly wouldn't trust them (especially for the S63). My car never goes to the dealership, as I only trust myself or one independent mechanic I know. The engine is a heck of a piece of engineering, but I wouldn't mind it being a bit less complicated. Lots to go wrong on that thing and no space in the engine bay!
 
Stick to 5W40. Motul X-Cess 5W40 GEN2 has very good HTHS of 3.0cP.
That engine has a lot of issues, which are not only related to oil, like cooling lines, etc. I think TU resolved valve stem issues.
Personally, I would also run coolant that is bit more diluted. In England, you don't need a 50-50% coolant mix. I would go 70% distilled water as that will dissipate heat better.
One of the ways BMW tried to mitigate issues on N/S63 is running lower temperature oil cooler thermostats. You won't be able to avoid these issues, but running 5W40 oils and do 5k mile changes as well as running diluted coolant might help a bit.
Stick to LL01.
 
I was going for whether or not your engine runs high oil temps overall vs. temp difference between oils. If it does run hot temps with your driving style, higher HTHS will be your friend. Low Noack is beneficial for high temps, but with 2K per year (which is when I would OCI), and no top up, it doesn't matter much. Don't be concerned about low SAPS unless you're burning oil, again, won't cause significant deposit problems. Nor will a higher SAPS necessarily provide "better" protection. Oil formulations are very balanced with regard to SAPS content and if it meets approval, will provide solid protection.

Don't sweat or lose sleep over the bearings if you already know/anticipate they are a maintenance item. Whatever you choose to use that is approved will be fine. When they go, they go. Doesn't the S63 use the newer, hardened bearings?
 
Stick to 5W40. Motul X-Cess 5W40 GEN2 has very good HTHS of 3.0cP.
That engine has a lot of issues, which are not only related to oil, like cooling lines, etc. I think TU resolved valve stem issues.
Motul X-cess was one of the oils on my list, but I was questionable about it based on the SAPS content. It sounds like the consensus is that SAPS content should not be a primary factor here, so that actually opens the floor up to many more oil options. I've consistently seen M5 guys mention Motul X-cess and Liqui Moly Molygen as great options. As Ravenol is harder to get in the US, I think it's talked about less on forums, but I still see it discussed from time to time.

I certainly agree with you that the S63 is a bit of a diva, but it's hard to do better in the HP per $ equation (at least what they sell for in Europe). An immaculate, low mileage example sells for no more than £25k in the UK. I have the most updated version of the engine in my 2015, so my understanding is the valve stem seals are much less prone to issues (I do keep waiting to see blue smoke from the exhaust, though). It also has the updated injectors, so is less prone to hydrolocking from them sticking wide open (but it still happens and injectors are also a maintenance item in my book).

Doesn't the S63 use the newer, hardened bearings?
It seems like most M engines over the last 30 years have had some form of rod bearing issue. You'd think that BMW would have engineered this out by now. The F10 M5 was the first car to get the S63 engine. Although they made some improvements on the S63s in the 2014-2016 F10s, I've never heard that the rod bearings are different within the F10 generation. The F90 M5 (2018-2024) also got the S63 and I know they made some additional improvements for this generation (specifically the HP fuel pump), but the rod bearings may have been part of this upgrade as well. Either way, I know the F90 guys are talk about total engine failures from rod bearings, so the issue certainly wasn't fixed entirely.

They've kept the S63 in the brand new M5 as well (which is technically a hybrid now . . . and VERY overweight). It's not clear yet if they've now finally fixed the rod bearing issue for good, but I would not bet on it.
 
If either LL-01 or LL-04 are truly interchangeable, is there any measurable pro/con between them in this application? Again, I read somewhere that a higher SAPS content can provide better overall engine protection (but maybe my frequent oil changes negate this benefit of a higher SAPS oil). Maybe focusing on metrics like the lowest NOACK and highest HTHS may be more beneficial?

I'm not sure what BMW recommends for oil intervals in the UK, but I certainly wouldn't trust them (especially for the S63). My car never goes to the dealership, as I only trust myself or one independent mechanic I know. The engine is a heck of a piece of engineering, but I wouldn't mind it being a bit less complicated. Lots to go wrong on that thing and no space in the engine bay!
It had been mentioned, via second or third hand , over ~20 years ago with the change over to ULSD/ULSG that there is a difference in wear at extremely high miles. But that was a long time ago and it has never been disclosed publicly. BMW periodically revises all of their approvals like other European automakers.

I've always wanted a F90 M5. Perhaps one day.
 
Have you considered preventatively replacing the bearings?

That said, my close friend drove over 175k miles in his M6 with the same engine and didn't do any special maintenance or use special oils...just took it to the dealer...then later an independent BMW specialist. But once he hit 170k his indy told him this was a "miracle car" and to get rid of it before it decides to blow up the engine. He never did the bearings. Though once he hit 90k I told him he was on borrowed time and should replace those bearings....but the time never came. He never even had to do a clutch...though it was replaced under warranty at around 30k a single time.
 
Wow, thank you all for the very prompt replies!


Regarding engine temps, the F10 M5 thankfully has oil temp on the dash (instead of coolant temp). I know this will sound odd, but when I first got the car and it had 0W-30 in it, it seemed to run a bit cooler than when I changed to the 5W-30 Ravenol. With the former it sat dead on the 95C mark, while with the latter it will sit just a bit above, so probably around 100-105C. The marks are in 25C increments, so it's hard to be precise. I could also just be completely nuts about the different oil temps, but I swear I cannot recall the car ever going above the 95C mark until Ravenol went in.
LSJr recently did a UTube video on PAO base stocks.
Basically PAO oil runs hotter because it's much better at cooling the engine. Which is good.
Is the Ravenol PAO base?
Castrol Edge 0W40 or Sell Helix Ultra 5W40 are my go to.
Castrol Edge Supercar 10W60 is the BMW M oil. There are Mobil 1 in 5W50 and 15W50.
In England don't worry about the Winter rating, even 25W goes down to like -25 oC.

Personally I'd try the Castrol Supercar and see how that went. Or another 50 oil with PAO.
 
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The consistent activity in this forum is really refreshing to find. It feel like the good 'ol days of car forums of 20 years ago!

Have you considered preventatively replacing the bearings?

That said, my close friend drove over 175k miles in his M6 with the same engine and didn't do any special maintenance or use special oils...just took it to the dealer...then later an independent BMW specialist. But once he hit 170k his indy told him this was a "miracle car" and to get rid of it before it decides to blow up the engine. He never did the bearings. Though once he hit 90k I told him he was on borrowed time and should replace those bearings....but the time never came. He never even had to do a clutch...though it was replaced under warranty at around 30k a single time.
I went into the purchase of this car with my eyes wide open, knowing that the injectors and rod bearings would be "maintenance" items. I'm just trying to do what I can to be gentle on the bearings, which in addition to oil, also includes the way that I drive the car. I fully anticipate replacing the rod bearings before I hit 50k (car is at 38k now).

Your friend definitely had a unicorn of an S63 engine there! There are a couple guys on the M5 forums who have had shockingly good reliability well past 100k miles, but they definitely are not skiping on maintenance. That might be one of the highest mileage S63s around, though. 175k+ is insane!

LSJr recently did a UTube video on PAO base stocks.
Basically PAO oil runs hotter because it's much better at cooling the engine. Which is good.
Is the Ravenol PAO base?

Castrol Edge Supercar 10W60 is the BMW M oil.
I'll have a look at the video; thanks for the tip. Yes, almost all the Ravenol engine oils are PAO-based. From my last round of research a year ago (which is actually when I found this forum), I recall the benefits of PAO was one of my reasons for choosing to go with Ravenol. I recall reading one of the downsides of PAO is that it can harden seals, but Ravenol states they add something to the oil to counter this. I have no idea if there's any material difference in how long a rear main seal would last with non-PAO vs PAO oil, though. However, I didn't realize that a PAO-based oil would run a bit hotter. This would explain why I saw the oil temps marginally eek up after I swapped to Ravenol.

Regarding the 10W-60 weight in M engines, I believe this weight was used in the E60 M5 with the S85 V10 engine (the generation before my car). It may have also been recomended for other other M engines in this vintage (or older) as well, but I've never seen that weight recommended for the S63. I'm not sure I'd be comfortable making the jump up to that kind of weight, but it is feeling like a 5W-40 may be the sweet spot for my application.
 
LSJr recently did a UTube video on PAO base stocks.
Basically PAO oil runs hotter because it's much better at cooling the engine. Which is good.
Is the Ravenol PAO base?
Castrol Edge 0W40 or Sell Helix Ultra 5W40 are my go to.
Castrol Edge Supercar 10W60 is the BMW M oil. There are Mobil 1 in 5W50 and 15W50.
In England don't worry about the Winter rating, even 25W goes down to like -25 oC.

Personally I'd try the Castrol Supercar and see how that went. Or another 50 oil with PAO.
Ravenol has a PAO base stock.
 
Regarding the 10W-60 weight in M engines, I believe this weight was used in the E60 M5 with the S85 V10 engine (the generation before my car). It may have also been recomended for other other M engines in this vintage (or older) as well, but I've never seen that weight recommended for the S63. I'm not sure I'd be comfortable making the jump up to that kind of weight, but it is feeling like a 5W-40 may be the sweet spot for my application.
If the Ravenoll is PAO base it should be amazing in 5w40 for a stock engine.
0W40 Castrol Edge is also PAO apparently and runs well.

Yeah IDK about 10W60 in a S63.

I'll tell you a story from today.

I am in the final stages of the Stage 3.5 build of the B48 in my 530i. Big Turbo, flex fuel E50 etc. 30 psi.

I spoke with Nulon tech today, a Fuches company, he said because I was going to radically alter the engine that all the oil specs for the stock engine were now void, and to forget them.
Instead the focus is now on an oil which will give adequate film strength in the bearings after the effects of increased heat and ethanol have degraded it.
Based on this he wanted at least a 50 or even 60 oil.
We finally settled on a 15W50 which Is SP rated. The tech said it would shear down to a high 40.
He said a 30 would shear down to 10 cv100 and I'd blow my engine.
He also suggested I do an oil analysis (a service they offer) after a few thousand k and insisted that the oil is changed more frequently.
The big stand out was he primarily wanted a much thicker oil. Even the SP was a minor detail to him.
 
Personally, I would also run coolant that is bit more diluted. In England, you don't need a 50-50% coolant mix. I would go 70% distilled water as that will dissipate heat better.

Why would you want to lower the boiling point of the coolant in an engine that "runs hot?"
 
If it were my car, and i had easy access to to Ravenol RUP or RCS 5w40, I'd run either at annual oil changes, and change the filter every other year.
 
Why would you want to lower the boiling point of the coolant in an engine that "runs hot?"
It is not running that hot for the coolant to reach a boiling point if diluted.
Diluting coolant is standard practice on the track. I run in my BMW on track 10% coolant in summer as the track is at high altitude and heat dissipation is far more important. BMW runs cooling based on need. The more you push it, the cooler it will run bcs. DME will put the thermostat and water pump into effective mode. If you baby it, it will run hotter, as DME is putting water pump and thermostat in efficiency mode. The problem is heat over time. These engines are hot V, and any heat that can be shed off is a gain.
Audi actually recommends in the manual in S/RS models to run 10% if tracking a vehicle, meaning where extremely high temperatures are expected.
 
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If it were my car, and i had easy access to to Ravenol RUP or RCS 5w40, I'd run either at annual oil changes, and change the filter every other year.
I actualy emailed Ravenol and asked effectively the same questions I asked here. They weren't super responsive, and Germany ended up kicking me over to their UK entity. I was hoping for a technical person to respond, but instead got the Marketing Manager :rolleyes:. As such, I've mostly dismissed his technical feedback, but I did also ask some questions about their "racing" fluids. Specifically, I wanted to know if they have a different detergent pack in them. Here is what he said:

Regarding our motorsport oils like REP and RUP: while they offer incredible protection under extreme conditions, they’re not really intended for regular road use. These oils are engineered for sustained high loads and temperatures in race scenarios. They also tend to have a reduced detergent/dispersant package, which can make them less ideal for long-interval, stop-start driving. Our road-focused USVO oils (like VMP) actually share some of the same base oil technology, but they’re designed specifically for real-world, road-going use — which makes them a better choice for a car like yours that sees fast road driving but not track abuse.

I'd like to think he's probably right about this stuff, as a marketing guy should be able to explain basic differences in their products, so I'm thinking to stay away from their racing oils. If I were going to do a track day, it may be good to drop some in, but perhaps not for regular oil changes.

Getting back to rod bearings, personally I would try Mobile 1 5W50:
https://www.mobil.com/en/lubricants/for-personal-vehicles/our-products/products/mobil-1-fs-x2-5w-50
It looks like a PAO base oil as well and not amazingly thicker than a 40 like the 10W60 but will increase bearing protection significantly. A good compromise.
I think given your noticed improved oil cooling from the ravenol a PAO based oil is a must on this engine.
I definitely wouldn't go thinner than 5W40.
I appreciate all your input, and the story from the Nulon tech. The longer this thread goes on the more I'm getting convinced that a Ravenol (PAO based) 5W-40 oil may be best for me. At least I can try it this oil change, get another oil analysis, and see how things look next year.
 
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