Oil is asked to do more than battle friction. It now has to hold junk in suspension for longer drain intervals than ever before and even drive the camshaft phasers on some variable valve timing systems. In light of the new requirements, the American Petroleum Institute has introduced a new rating. The GF-5 kicks in on October 1st, 2010, and the spec calls for an increased capacity for deposits and longer life, as well as a lower propensity to sludging. With the turbocharger's resurgence, GF-5's call for better protection will keep those red-hot snails from creating coal in their bearings.
How does all of this help fuel economy? Thinner oils that perform like more gooey viscosities in terms of heat tolerance and deposit control siphon off less of the engine's power. An oil pump with an easier life means an engine that gets more work out of a gallon of fuel. In the future, we're likely to see oils like 0W-20 increase in popularity as fuel economy standards tighten.
[Source: Autoweek | Image: GF-5.com]