If you daily drive pretty hard, i wouldn't run Mobil 1 Extend Life for the full 15,000 miles. I'd think 10,000 would be pretty acceptable though. Changing oil more frequently can do nothing but good for your engine.

 

I been using Mobil 1 full synthetic for years in all my vehicles. I use the viscosity level recommended by the manufacturer.

The exception is my 2012 F150 EcoBoost......it's still under warranty and goes to the dealer for everything!

 

A friend works as a fleet mechanic at a large utility company. He told me they are using Mobil 1 full synthetic out to 15,000 miles, and changing the filter every 5,000 miles. He seems to think it works as long as you change the filter often.

 

I run Royal Purple in about all my vehicles except for my 77 granada beater only because the engine is wore and when you add synthetic to a wore engine you tend to loose more oil due to it's better lubrication properties.

This is also a really good deal well better than Walmart or any of the local auto parts store, sure wish I lived closer than 100 miles to Summitracing!

37.97 for 5 quarts what a deal
http://www.summitracing.com/parts/rpo-51530/overview/