Originally Posted By: Panzerman
The reliability of the 4.6 or alot of other engines, has far more to do with the superior designs of the motor then the oil going through it. Alot of those taxi/limos are operated on 10w30(alot cheaper in bulk) or some even fleet oils, such as 15w40(we did this for years in PA without incident).Remember, cars generally run a thicker oil in other countries without any less reliability or problems. Lubrication problems are unussual, its usually the lack of oil or neglected oil changes that lead to problems. The cooling and fuel problems are much more common. Iam starting to believe that the manufactures run the 5w20 in their most reliable engines to get the cafe advantages. The troublesome designs seem to still spec 5w30 or in some cases even 10w30.
Agreed. The 4.6L is also not overpowered for its design. It burns very clean with minimal blowby, thus being very easy on the oil. Take the chrysler 3.5L for example, much harder on the oil, very powerful for its liters, and tends to shear the oil by 5k.
It really all depends on what the engine likes. With the price of fuel goin up, I truly think 10w-30 will become "old school" and with more public faith, 5w-20 will be the norm and 5w-30 will be the next best.
I myself still like 5w-30 and could go to 5w-20 but would like to see a few more success stories of it being just as good.