We have been using Rotella (non synth) in all our farm engines both gas and diesel for many years now. We buy it in 55 gal drums. I believe it has performed as well as any could, but mind you, we are quite particular about changing oil on a schedule. For diesel tractors, every 100 hours, for the cars, every 3000 miles, etc.

On my 300D, I started using the Rotella synth 5W40 last year and have noticed a reduced oil consumption as a result. I change it about every 5000 miles since it's a highway driver almost all the time.

BTW, my dad bought a new 84 Olds Toronado with a 350 engine and has used Mobil 1 in it forever, (an exception to our usage described above) The Olds has about 310,000 miles and the engine hasn't had a wrench on it yet. Everything else on that car has fallen apart, but the engine is perfect and doesn't leak or use oil at all.

__________________
DS
2010 CL550 - Heaven help me but it's beautiful
87 300D a labor of love
11 GLK 350 So far, so good
08 E350 4matic, Love it.
99 E320 too rusted, sold
87 260E Donated to Newgate School
www.Newgateschool.org - check it out.
12 Ford Escape, sold, forgotten
87 300D, sold, what a mistake
06 Passat 2.0T, PITA, sold

Las Vegas NV