Viscosity of Synthetic oil in the bottle

[JLR]

Dr. Haas said this in an old Motor Oil University;

"This is worth repeating: The synthetic 10W-30 grade oil is based on a heavier 30 grade oil while the mineral based 10W-30 oil is based on a thinner 10 grade oil. They are both similar at
operating temperatures yet the 30 grade based synthetic is actually less thick at startup and much less honey - like at low temperatures. This is the opposite of what common sense
dictates."

I take this to mean the oil in a Mobil 1 10w-30 bottle is a 30 grade and the oii in an old can of mineral based Gulf Multi- G 10w-30 is a 10 grade. Help me out here.

 

[Quattro Pete]

There are a lot of inaccuracies/oversimplifications in Dr. Haas' writings, including the one you quoted. See here:
https://www.bobistheoilguy.com/foru...902/dr-haas-motor-oil-university-article

Some forum members (mainly Solarent) have rewritten Dr. Haas' initial document to correct a lot of these inaccuracies. The updated version is on BITOG's main page:
https://www.bobistheoilguy.com/motor-oil-101/

 

[y_p_w]

The requirements for the 10W and the 30 are at far different temperatures. Everything in between can happen. The Mobil 1 0W-40 that I use is thicker at most ambient temps than most common 5W-20s. Also - the W number is supposed to be a minimum requirement. I understand that it's possible to exceed the requirements for low temperature pumping.

I always thought that saying that a motor oil is "10W-30" isn't necessarily the best way to describe anything because there are so many different ways to get there. Manufacturer specifications may be a better way. Now there's also that engines can be tolerant of a wide range of engine oils. You're always starting when the oil is thick, and running it when it's really thin.

 

[kschachn]

Originally Posted by y_p_w
The requirements for the 10W and the 30 are at far different temperatures. Everything in between can happen. The Mobil 1 0W-40 that I use is thicker at most ambient temps than most common 5W-20s. Also - the W number is supposed to be a minimum requirement. I understand that it's possible to exceed the requirements for low temperature pumping.

It has to be labeled with the performance it achieves.

 

[CT8]

I would not Consider Dr.Haas oil 101 a valuable source of information. I am so amazed that people believe anything on the TV or internet.

 

[dogememe]

lol

 

[oil_film_movies]

Originally Posted by JLR
Dr. Haas said this in an old Motor Oil University;

"This is worth repeating: The synthetic 10W-30 grade oil is based on a heavier 30 grade oil while the mineral based 10W-30 oil is based on a thinner 10 grade oil. They are both similar at
operating temperatures yet the 30 grade based synthetic is actually less thick at startup and much less honey - like at low temperatures. This is the opposite of what common sense
dictates."

I take this to mean the oil in a Mobil 1 10w-30 bottle is a 30 grade and the oii in an old can of mineral based Gulf Multi- G 10w-30 is a 10 grade. Help me out here.


A synthetic 10w-30 has the same kv100 (hot viscosity) as a conventional 10w-30, obviously, right?
You do have to formulate the conventional with thinner base stock oils, and that is what Haas refers to there.
Why? The synthetic naturally meets the 10w cold visc requirement using less, or even zero, VII chemicals, where a conventional 10w30 must use thinner base oils and have it's kv100 propped up (increased) to about 10 cSt by more VII.
So he's basically right.

 

[DGXR]

Originally Posted by y_p_w
You're always starting when the oil is thick, and running it when it's really thin.

I've always subscribed to the general idea that a multi-viscosity oil is trying to achieve a more consistent stable viscosity across a temperature range.
For example, a 10w30 acts like a 10w ("thinner") at cold temperatures, and acts like a 30w ("thicker") at full temperature. But the actual viscosity at those temperatures is closer to the same value because of the VII additives. In contrast, a straight 30w will be "thicker" at cold temperatures and act just like a 10w30 (i.e. "thicker") at full temperature... and vice-versa for a straight 10 weight... although nobody would run that in their motor!
I'm not sure if this makes sense but I explained the best I could.

 

[y_p_w]

Originally Posted by kschachn
Originally Posted by y_p_w
The requirements for the 10W and the 30 are at far different temperatures. Everything in between can happen. The Mobil 1 0W-40 that I use is thicker at most ambient temps than most common 5W-20s. Also - the W number is supposed to be a minimum requirement. I understand that it's possible to exceed the requirements for low temperature pumping.

It has to be labeled with the performance it achieves.

I heard something about that, but I thought there had to be some sort of leeway. That being said, it's a blunt tool. It's measuring pumping at a ridiculously low temperature and viscosity at a typical operating temperature. Then there's viscosity in between, which is probably what the OP is asking about.

I don't really that claim the OP brought up. My understanding about 90s era Mobil 1 10W-30 was that it achieved its multi weight properties using a PAO-ester blend that inherently had a high viscosity index and used little or no VI improver. But a group I 10W-30 oil would be formulated with VI improver.

But it's not "10 wt" oil packed with VI improver. And these days "conventional" 10W-30 would be made with Group II base oils that have higher VI. I thought it's supposed to be carefully formulated where the entire additive/VI improver/base oil package meets the desired multi weight properties. A "conventional" 10W-30 from the same brand doesn't exactly have the same base oil as a 10W-40 from the same maker.

 

[OilUzer]

Doesn't a 10W need to pass 10W requirements and fail 5W requirements to get the honor of being a 10W?
From that point of view, one would think that 10W syn & 10W dino are more similar than different.