UOA & cSt Viscosity @ 100° ?

[tsduke]

Ok, trying to learn more on these tests.

If a 30wt oil should be at 10 I'm not sure I understand why some used oil analysis are considered good. I've scanned through several of the 5w30 used oil analysis and see some in the mid o upper 8's and several in the low 9's, but Blackstone doesn't say anything negative. I've also noticed that I'm seeing different ranges under "Values Should Be*" just for 5w30 oils.

What's the science here?

 

[d00df00d]

Originally Posted By: tsduke
Ok, trying to learn more on these tests.

If a 30wt oil should be at 10 I'm not sure I understand why some used oil analysis are considered good. I've scanned through several of the 5w30 used oil analysis and see some in the mid o upper 8's and several in the low 9's, but Blackstone doesn't say anything negative. I've also noticed that I'm seeing different ranges under "Values Should Be*" just for 5w30 oils.

What's the science here?

There isn't much good science where Blackstone used oil analysis are concerned, at least as far as what they tell you.

However, the oil's kinematic viscosity at the end of the UOA is only a small piece of the puzzle. Unless you have other indications of a problem, it's really nothing to worry too much about.

 

[webfors]

A lot of conventional 30 weights shear a point or two over the interval in some applications. Anything 8.5 and higher would satisfy me as long as other variables check out.

 

[tsduke]

Originally Posted By: webfors
A lot of conventional 30 weights shear a point or two over the interval in some applications. Anything 8.5 and higher would satisfy me as long as other variables check out.


It was only looking at 5w30 syn tests. I think the one I saw that was like 8.8 was PP.

 

[Fallguy]

Originally Posted By: tsduke
Ok, trying to learn more on these tests.

If a 30wt oil should be at 10 I'm not sure I understand why some used oil analysis are considered good. I've scanned through several of the 5w30 used oil analysis and see some in the mid o upper 8's and several in the low 9's, but Blackstone doesn't say anything negative. I've also noticed that I'm seeing different ranges under "Values Should Be*" just for 5w30 oils.

What's the science here?


I agree and have seen many Pennzoil Platinum Ultra & Castrol Edge falling out of 30 grade.

Look at Valvoline SynPower and you will not find it falling out of grade for the most part. Starts at 10.5 maybe that helps or they use higher base stock, dont know but I find it unacceptable for a synthetic to fall out of grade.

They state some engines may shear oil more than others and that could explain some of it ?