Mobil 1 Supercar 5W-50, 1.1k mi; C8 Z06

[MitchB]

This was a wellness check - sample only.

Car was layed up over winter. Oil changed end of December. Not started/run for 5 months.
Cranked engine no fuel 3 times before firing off.
Several sustained 130-150 runs for ~10 minutes at a time. Otherwise, mostly highway driving.
Consistent relatively high rate of fuel dilution since new. Minimal idling.
Amsoil upper cylinder lubricant corrosion inhibitor used each fill up.
Oil life monitor at 48%

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[fantastic]

Interesting the 5w-50 SuperCar has noticeable lower oxidation reading than the 0w-40 does. Not sure why they flagged viscosity since it's a 5w-50 15.5 not bad but curious what it will be with a few thousand on it. Do you plan to resample with more miles?

 

[MitchB]

Published data from Mobil 1 reports their 5W-50 kinematic viscosity @ 100C as 18.1. Virgin 5W-50 testing has given this as 15.98. A 40 weight oil is classified as having a kinematic viscosity @ 100 degrees celcius in the range of 12.5 to 16.2. So, testing has shown this oil - Mobil 1 supercar 5W-50 as a borderline 40 wt oil right out of the bottle. Plus, it has a high shear rate. Combine this with fuel dilution and this is why I do oil changes with relatively low mileage. I will most likely end up doing my next oil and trans service in the next few hundred or so miles.

 

[Hohn]

Published data from Mobil 1 reports their 5W-50 kinematic viscosity @ 100C as 18.1. Virgin 5W-50 testing has given this as 15.98. A 40 weight oil is classified as having a kinematic viscosity @ 100 degrees celcius in the range of 12.5 to 16.2. So, testing has shown this oil - Mobil 1 supercar 5W-50 as a borderline 40 wt oil right out of the bottle. Plus, it has a high shear rate. Combine this with fuel dilution and this is why I do oil changes with relatively low mileage. I will most likely end up doing my next oil and trans service in the next few hundred or so miles.

Sounds like you need a more shear stable oil that’s closer to middle of 50 grade and stays there.

 

[Nathan]

Change early and often is a great strategy, especially during a warranty period.

The only other option I know of is Redline 5w50 but maybe after warranty expires.

What's the reason for the Amsoil additive? Do you run ethanol?

 

[MitchB]

I have always used an upper cylinder lubricant going back many years and considering the properties of commercially available gasoline has changed significantly, especially being ethanol blends, I think the benefits are significant.

 

[MitchB]

While I have stockpiled enough Mobil 1 Supercar 5W-50 for my next 3 oil changes, I will be coming up on my next engine and transmission service and I might instead use something like a 15W-50 or 20W-50 PAO/ester blend like Redline or Motul. If I do, I will use oil analysis so I can compare the data.