Your post is funny. Clearly, thinner oils don't destroy engines which spec a thin oil. AGREED Will a 5w30 cause more wear in a performance engine which specs 5w40? MOST LIKELY I wish the world wasn't in an oil crisis that it's in today where automakers could use whatever oil viscosity they want (if they were interested in keeping the engine running forever vs basically forcing you to come back and buy a new when your current engine blows) as it would be interesting to see which direction the oil viscosity trend would be heading... North or South.
Originally Posted By: D189379
I bet the extra engine wear from using a lighter weight oil is as insignificant as the 1% mileage you gain. Who cares? Clearly lighter oils don't destroy engines, nor do they save you huge amounts of fuel.