Question about Dr. Haas' Article

[kartracer55]

After some lengthy reading, I came up with one or two questions that I could not find the answers too and would greatly appreciate some clarification on the matter, as I am quite interested.

First, If Synthetic 10w30 is based on 30 weight oil, and conventional 10w30 is based on 10w mineral, (in lamens terms) How/why is the Synthetic oil still thinner?

Also, If the Bottle is labeled as 10w30, How is it that when it supposed to act as a 10 weight on cold startups, that it gets thicker, then thins out as it gets up to operating temperatures?

Clarification on this matter would be great, because I am having a bit of problem fully understanding the concept

Thanks

Jim

 

[kartracer55]

I meant to say still thinner on cold startups

 

[JAG]

Originally Posted By: kartracer55
First, If Synthetic 10w30 is based on 30 weight oil, and conventional 10w30 is based on 10w mineral, (in lamens terms) How/why is the Synthetic oil still thinner?

It may not be. For super cold viscosity data, you should look at the CCS and MRV numbers for both oils in question. Lower means easier engine cranking and oil pumping, respectively. Many product data sheets don't include that data though. How an oil behaves in an engine is not based on kinematic viscosity. That's why they take cold cranking and pumping viscosity measurements instead of just taking kinematic viscosity measurements while letting the oil low through a tube under gravity.

Originally Posted By: kartracer55
Also, If the Bottle is labeled as 10w30, How is it that when it supposed to act as a 10 weight on cold startups, that it gets thicker, then thins out as it gets up to operating temperatures?

Every motor oil thins as it gets hotter. XW-Y is a classification that was stupidly developed and they are sticking to it. Check out a SAE J300 table and try to make sense of it. If not, let us know.