Low Rotella T6 viscosity against tds

[vinu_neuro]

I always wondered why the visc on used oil analysis for this oil were so low compared to the published data, 14.2 cst. Despite what Shell says, what they put in the bottle is 4-5% lower viscosity. I'm happy about it as it lowers the HTHS from 4.0 to around 3.8. Just interesting that what they're bottling is consistently so far off the tds.

Here are three VOA's of T6:

https://bobistheoilguy.com/forums/threads/shell-rotella-t6-5w40-voa.158546/
http://www.bobistheoilguy.com/forums/ubb...470#Post1939470
https://bobistheoilguy.com/forums/threads/rotella-t6-5w-40-manufactured-01-27-12.172253/

 

[JHZR2]

You're assuming that the analytical equipment is all calibrated the same.

 

[dparm]

There are always production variances, and that's not something that Shell is going to volunteer. I'd bet it could be as much as +/- 10%.

 

[Quattro Pete]

Seems to be a pattern. The old formulation of this product (T 5w-40) also tested below the spec. I've seen VOAs showing 14.2 - 14.5 while the TDS showed 15.5 cSt.