Toshbar

If you think that specifications on recommended oil viscosity are based solely on what engineers say, I have a bridge to Hawaii to sell you.

Auto companies receive tax credits/incentives from the EPA if they recommend 'energy conserving' (thinner) oil in the literature.

Mod (Ret.)

As it was already stated, some countries do not offer or sell certain oil viscosities, and owners manuals for vehicles that are sold there recomend a different oil viscosity for them. I worked in Germany for 5 years, and at that time, my 2005 truck was driven on their roads. 5w-20 was not sold there, and I used 10w-30, which was recommended by the Ford dealer in Germany. New engines are built with much better and tighter tolerences then those in the past, and can run on thinner viscosity then older built engines. This can provide perhaps a slightly better MPG rating.

screamineagle

The smarter folks here will not agree with this. An abused 5.4 3v will not run long!

Mod (Ret.)

^^^ Good point. There's a recent thread here that stated a newly purchased F150 5.4 owner had to have the engine replaced at only 56K on its odometer. Lucky for him it was done by the place he bought it from (Carmax?), as it had noisy cam phasers and scored cylinder walls. While the cam phasers are a known issue for early built 5.4's, I'd think that scored cylinders at 56K is due to poor prior maintenance.

Ive not owned a 5.4 (yet), but my 2005 4.2 V6 carried me over 179K of trouble free miles before I traded it in on a 2001 Ford Ranger 4x4 with 3.0 V6. That got me to 235K miles, and I'm now driving a 2007 F150 with the 4.6. It has 128K, and running strong.

All of these have used, or are currently using 10w-30 oil.

bubbabud

Putting 2 handfulls of sand in the airbox helps to break the glaze on the cylinder wall allowing the rings to seat and prevent oil burrning.

Martian

When was your last desk pop?

650NutKase

By abused, I meant being used in a tough work environment. I get it, you don't agree with my statements. Point noted LOL

bubbabud

Chill written in jest