2021 Mercedes AMG C63S - 10k miles - M1 FS 0w40

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This is the second oil change my 2021 C63S has received and the first full interval using Mobil 1 FS 0w40. This car is a daily driver but I don't have any sort of daily commute.. I do like winding it out to hear that V8 pop and bang! The car has the hand-built, wet sump M177 bi-turbo 4.0L V8.

Actually a bit surprised that it was able to shear down M1 0w40 so far, and almost 10 quarts worth of it, but it doesn't seem to have caused an issue.

Screenshot 2022-09-24 124612.jpg
 
Everything looks good. Most 0w40's are going to lose a bit of their viscosity. It's rare you see a 0w40 that doesn't. Redline is one of the few that may not.
 
Everything looks good. Most 0w40's are going to lose a bit of their viscosity. It's rare you see a 0w40 that doesn't. Redline is one of the few that may not.

Probably right. Even the Mobil 1 ESP 0w40 in my Corvette would shear a little. The Motul 300V 0w40 generally did not, but it also costs twice what M1 does...and isn't MB-certified.

I think these 5k intervals will work fine given my driving habits. TBN and TAN still look fine.
 
Confusing title. I was expecting a 10,000 mile oil run.

5k intervals look good to me. PLENTY of buffer room.
 
Confusing title. I was expecting a 10,000 mile oil run.

5k intervals look good to me. PLENTY of buffer room.
Pleanty of buffer means too much buffer :)

Given the insol at 0.1 and the TBN at 5, that oil should be run at at least 2500 miles longer.
It's being wasted now dumping at 5K.
 
I had the same experience with M1 0W40, 100 deg viscosity of 10.0 after a ~5K run...DI turbo high-power dense engine, likely some fuel dilution that BS doesn't really accurately reflect but with your last change the flash point is still pretty high. I'd say 5K is a good interval here, at 10K you'll be getting thinner and thinner so why push it?
 
The one time I used M1 0W40 in our 06 Infiniti M45, it finished at 12.0 after 4700 miles (and TBN of 5.6). I guess it depends on the engine. I do agree that you should safely be able to push it another 1000-2500 miles.
 
The one time I used M1 0W40 in our 06 Infiniti M45, it finished at 12.0 after 4700 miles (and TBN of 5.6). I guess it depends on the engine. I do agree that you should safely be able to push it another 1000-2500 miles.
B/c no turbo.....
 
Yea, let's risk an engine costing 10s of thousands of dollars to save 20 bucks on oil :rolleyes:

Switch to another oil or stick to your OCI, or even shorten it (I would).
 
Great looking report. If you are concerned about fuel dilution, use a different lab like Polaris/OAI. While most viscosity loss is due to fuel, 0W-40's have a pretty wide spread and so some mechanical shear is pretty much inevitable with your typical commercial offerings. M1 0W-40 is one of the best oils on the market, so I wouldn't be concerned regardless.

Everything looks fantastic for such low miles.
 
Yea, let's risk an engine costing 10s of thousands of dollars to save 20 bucks on oil :rolleyes:

Switch to another oil or stick to your OCI, or even shorten it (I would).
Exactly - with the viscosity drop it's a no-brainer to do 5K changes on this car.
 
Great looking report. If you are concerned about fuel dilution, use a different lab like Polaris/OAI. While most viscosity loss is due to fuel, 0W-40's have a pretty wide spread and so some mechanical shear is pretty much inevitable with your typical commercial offerings. M1 0W-40 is one of the best oils on the market, so I wouldn't be concerned regardless.

Everything looks fantastic for such low miles.
I need to do the math but....with a 10qt fill how much fuel as a % needs to be in there to drop an oil starting around 12.5 down to 10? I have always believed that this is in-part due to fuel but some of this is mechanical shear which many say w/r this M1 0W40 shouldn't happen with it's "more: group IV base".
 
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I need to do the math but....with a 10qt fill how much fuel as a % needs to be in there to drop an oil starting around 12.5 down to 10? I have always believe that this is in-part due to fuel but some of this is mechanical shear which many say w/r this M1 0W40 shouldn't happen with it's "more: group IV base.
It's 10.97, so it's 11 for all intents and purposes.

Crude math, using the Widman calc, 4% fuel to get to 10.89cSt.
 
It's 10.97, so it's 11 for all intents and purposes.

Crude math, using the Widman calc, 4% fuel to get to 10.89cSt.
Ok that isn't much and well within the realm of what you could see and yes, I goofed for some reason I though this was closer to 10 but it's nearly 11, not bad at all considering it's barely a 40W.
 
It's 10.97, so it's 11 for all intents and purposes.

Crude math, using the Widman calc, 4% fuel to get to 10.89cSt.
With a flashpoint of 430 (I've seen a VOA of M1 0W40 that shows virgin FP of 435), we have no way of knowing for sure how much viscosity loss is due to fuel vs. mechanical shear. This is one case where it would make a lot of sense to do the next UOA with a lab that uses gas chromatography.

Yea, let's risk an engine costing 10s of thousands of dollars to save 20 bucks on oil :rolleyes:
I can see both sides. On the one hand, I can't see how running such a stout oil just a little further when all indications are that it has plenty of life left can possibly "risk an engine". On the other hand, if you have the resources to afford such a car, then saving a few bucks or helping the environment might not be at the top of your list.
 
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