I was in Walmart the other day picking up my Mobil 1 5W-20 oil and had some down time to look around and saw this oil I, personally, had never seen before and it got me to thinking. It was Mobil 1 0W-20 Advanced Fuel Economy. From the Mobil 1 website it says,

"For improved fuel economy, consider using Mobil 1 0W-20 Advanced Fuel Economy which is engineered to deliver outstanding engine protection and to offer improved fuel economy in vehicles where SAE 0W-20 or 5W-20 oil is recommended." (http://www.mobil1.com/usa-english/mo...ilOption2.aspx (http://www.mobil1.com/usa-english/motoroil/car_care/which_oil/WhichOilOption2.aspx))

Yes, I'm in the south (North Carolina) where it's legitamately warm so cold temperatures, even with Spring here, isn't really a problem. Now when I think of a 0 wieght oil, I think of one like you would flush your block with and never get to normal operating temperature and strenuishly drive before pulling the plug and filling back up with 5W-20.

So whats the deal. I get that lower oil consistency will be less strenuish on the engine therefore allowing for better gas mileage, though I don't expect this increase to be legitamately larger. What do we think about 0 weight oil and is there anything to this Mobil 1 0W-20 Advanced Fuel Economy?

It's spelled strenuous.

The engine oil has to heat up to 212 F to reach operating temperature, so even room temperature is "cold" for your engine oil. The 0W part means it's thinner at some specific temperature. You will reduce oil pumping losses by using 0W-20, but I can't predict what kinds of gains you'll see.

Yeah, of course a lower weight is going to flow more easily and what "gain" from that would be negligible. However, in terms of manufacturer suggested oil weight, is deviating from this going to, in the long run, negatively affect the engine.

Oh and I'm a prodigy of the spell check generation and the forum doesn't have this asset.

I've read that going to a lower cold weight oil can improve engine life. There's people who stand on both sides of this fence, though. You can read through some posts at the forums on bobistheoilguy.com and decide for yourself.