Mobil 1 viscocity between 0w-30 & 10w-30?

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Staff member
May 27, 2002
Guelph, Ontario
This is entirely possible. It simply shows that there are different levels of VII in each of those two oils. In order to be a 30wt oil, it has to show a kinematic viscosity of between 9.3cst to 12.5cst. So technically you could have one 10w30 oil with a rating of 9.4cst at 100c, and another 0w30 oil with a rating of 12.4 at 100c.

This is why it's important to look at the technical data on an oil when choosing a viscosity, just so you know if you're getting an oil at the bottom, middle or top end of that particular weight. I'm not too comfortable with the 10w30 oils out there that are lower than 10cst at 100c myself. I prefer them to be a bit higher than this.
Here is a graph to serve as a visul aid.

The 30C and 110C have no basis in fact and are intenentionally exagerated for effect, but are there to show what is likely happening.

Based on what I have seen in analysis, I have no problem with M1 SS running a little thin.

Originally posted by Jay:
In the old TriSyn formula the 0w-30 was the thinnest of Mobil 1's 30 weights. Now it's the thickest.

But the 10w30 is less volatile (has less VII) and a lower NOACK
I was reading the product data sheet on the Mobil 1 website and noticed that the 0w-30 viscocity Kinematic, cSt @ 100°C = 10.1 but the 10w-30 viscocity Kinematic, cSt @ 100°C = 9.8
How does a "technically" thinner oil actually have a higher vis at temps? or am I reading this wrong?
Thanks in advance!
You are correct - the temp/viscosity curves of the different oils actually cross.
The graphs I got from Mobil are enlightening for those interested. Files vta019a.pdf and vta018a.pdf for M1 and conventional dino respectively.
BTW the 0-30, 5-30 and 10-30 Mobil-1 lines are so close together on the graph between freezing and 212 deg F that they could almost be considered the same.
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