Inconsistency on Schaeffer spec sheet

[A_Harman]

I have been studying diesel 5w40 synthetics to put in my truck on the next oil change. The Mobil 1 Turbo Diesel Truck that I currently run is showing higher consumption than the VPB Classic I was running before. I like the Schaeffer 9000 oil, but after reviewing the spec sheet, I have found an inconsistency.

The sheet lists the following viscosity specs:
KV40 = 85.5-89.0
KV100 = 13.50-15.75
VI = 159

I have never seen a pds that lists a range of kinematic viscosities for an oil, but perhaps Schaeffer's is being conscientious by showing production tolerances. The problem comes when I try to reconcile the Viscosity Index with the Viscosity ranges.

Assuming the VI is correct, the expected KV100 numbers would be 13.5 and 13.9, corresponding to the KV40 numbers of 85.5 and 89.0. This would make it a very light 40-weight.

OR

Assuming the listed viscosity ranges to be correct, the expected VI would be 175 if mid-range values were assumed for KV40 and KV100. This would make it a mid-range 40-weight with VI competitive with many other 5w40's.

Depending on which of the listed values I use for the KV40 and KV100, I can get VI's ranging from 154 to 197.

Who knows which is correct?

 

[Food Scientist]

Using the VI calculator on this website, I just typed 159 and got 89 for KV40 and 13.83 for KV100. Looks to me that the numbers they used to calculate VI are different than the upper and lower numbers that define the range, but are still within the range.

I wouldn't worry about it because regardless of how good an oil looks on paper, without a trended UOA you will never really know.

 

[BobFout]

Isn't KV of 13.5 to 15.75 just the SAE range for 40 wt?

 

[A_Harman]

No, the range of vis for 40-wt is 12.5 to 16.3.