0W-30 Milage Increase

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Jun 16, 2003
Franklin, OH
Is the concensus of this forum that 0W-30 will have a measurable affect on mileage? My application is a '01 GM 5.3L 4X4. As far as brands, I am debating between Mobil 1 and Amsoil. I have used Mobil 1 in the past and noticed an increase in oil consumption. Could I expect this with Amsoil as well? The truck in question has not had synthetic in it and is currently using Castrol Syntec Blend 10W-30. I'm a little leary of 0W-30 oil and leaning towards the 10W-30.
I don't know about the Castrol but 0W30 M1 is actually a smidge thicker at temp than M1 5W30.

If you see a increase, it won't be alot if you are already running a 30W. My Kia Rio doesn't show a difference when I go from 0W30 to 5W30 M1.

BTW, I hardly use any oil in my 2000 Firebird with the 5.7 LS1. On average it uses less than a quart in 7K miles or so. Been useing 0W30 since it's third oil change at 3K miles. It know has 35K "hard" miles on it. This is basically the same engine as yours and they do have a reputation for useing M1 30W.

[ June 17, 2003, 03:58 AM: Message edited by: Judd ]
The more short trips you do the more likely that the 0W-30 will give better milage. But I doubt its significant. As Judd mentioned the 0W is a little thicker at operating temperature 10.3 vs 10.0.

[ June 17, 2003, 08:08 AM: Message edited by: Al ]
Actually it's not "thicker" even at operating temp. It may flow insignificantly slower with no shear forces but in any areas that count it will provide thinner film thickness. I.E. less drag. (which should translate into better economy)
Is that a compromise you are willing to make? For most drivers it probably doesn't matter.
As mentioned here, the greatest effect will be on numerous short trips especially with cold starts and at cold temperatures. As I see you're in Cincinnati, the you will see an effect (albeit a small one) during the winter months (Nov-Mar)...
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