Viscosity Index & Noack Oil Consumption

[Spector]

Okay, if I have an engine that is consuming oil and I wish to reduce that consumption am I correct in selecting an oil with as low a Noack number as possible coupled with as high a VI Index as possible.

Does that make sense???

 

[pinoy99]

Is this the Isuzu motor? What is the consumption rate?

 

[Spector]

quote:

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Originally posted by pinoy99:
Is this the Isuzu motor? What is the consumption rate?

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This is my camry. Was using a quart in 5-6000 miles with oil seal seepage and now consuming a quart in 3000 or so (Schaeffers) and seals have been replaced
Does have 169,000 miles though

 

[Whimsey]

quote:

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Originally posted by Spector:

quote:

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Originally posted by pinoy99:
Is this the Isuzu motor? What is the consumption rate?

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This is my camry. Was using a quart in 5-6000 miles with oil seal seepage and now consuming a quart in 3000 or so (Schaeffers) and seals have been replaced
Does have 169,000 miles though

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That's ironic about using more oil with Schaeffers. I noticed the same thing when I switched to Schaeffers 5w30 Supreme Blend. I started "using" oil where I previously didn't with Motorcraft 5w30 and Mobil 1 5w30

.
I've got to admit I'm a bit disappointed with the Schaeffers usage compared to these other oils I've used.

Whimsey

 

[427Z06]

One engine I had consumption issues right from the start is my '89 Toyota 3.0 GME engine. Dino and even Mobil 1 in the prefered grade of 10w30, would suck down a quart every ~1-2k miles.

Only thing that really helped was Mobil 1 15w50, but I was worried about it being to thick for cold weather so I tried some Castrol Syntec 5w50. Consumption was reduced to about a quart every ~6K miles so I continued using ever since. After being a BITOG for awhile now, I don't know if it was the smart thing to do, but the engine seems none the worst for it.

One variable that may make a difference is where the oil is being consumed from, e.g., the piston rings or the valve stem seals.

However, I'm starting to experiment with 5/15w40 grades in the effort of saving some money since the car is getting older now.

[ October 13, 2004, 04:46 PM: Message edited by: 427Z06 ]

 

[buster]

Spector, I think your assumption is right, but I had a mentioned to Tooslick once how Amsoil Series 2000 0w-30, with it's 8.6% Noak vs ATM's 5% burned off less. He said his customers noticed the same thing. He said their is something else to the oil that helps reduce consumption but wasnt sure what it was.

If you look at many people that have this problem with Mobil 1, it makes no sense. Their are other oils that are 10 to 11cSt like M1 that don't burn off like M1 does. Mobil 1 5w30's Noak is 9%, which is very good. So it's a mystery to me how this works. Mobil 1 0w-40 even had some issues with this. In fact my car burned more of Mobil 1 0w-40 then Series 2000 Amsoil. Makes no sense.

 

[47HO]

I think it would depend on why you are consuming oil. For instance, if your burning oil that has leaked around your valve seals, etc., I don't think it would matter.

 

[haley10]

It does make sense, but doesn't always work in actual practice. I have come to view VI as a somewhat empirical # more. Obviously it's only relevant to the "exact" same grade, e.g. 10w30. Comparing a 0-30 to a 10-30 VI would be meaningless.

Maybe, since better NOACK and higher VI might be a more viscous oil probably anyway.

If we're talking about consuming Amsoil here, I doubt switching products will make a big difference.

 

[Spector]

We are talking Amsoil
0W is 8.6 and 195 for VI
10W is 6.6 and 167 VI

Appears the 10W may provide less oil consumption?
Trying Schaeffers 15W40 now with Noack of 10.6 and VI index of 145 and this appears to be consuming more oil then the previous runs of 10W30.

 

[Blue99]

As Gene recently explained in a post, the VI index is the rate of change of the graph of an oil's viscosity from 40C to 100C.

The lighter base oils & VI improvers of a 5w30 generate a graph with a steeper line from 40C to 100C than a 10w30, thus the higher VI index number.

A mono grade such as SAE 30 or 40 will have a VI index somewhere around 100 and reflects the flatter graph line of a straight weight oil.

So, ideally, a lower VI index number & lower Noack volatility number (if an exact number is listed vs. less than 15%) would be your choice to help with consumption.

 

[haley10]

Spector the #'s look pretty typical. Generally, I think some full syn's can get a better ring seal, but low NOACK is better too. I'm not surprised that the ATM shows the lowest consumption.