Warning to new owners!!!!
#34
While I would agree with you to a certain degree. Bearing tolerance is very critical to a oil choice. However the difference we're talking when switching to something like a 5w30 or even 10w30 isn't all that different. A good friend of mine is a oil engineer at a fairly large oil company that primarily deals with motorsports and automotive oils. My last car a 4.6L 3V S197 spec'd 5w20, which was actually designed to run 5w30, but I ran 10w30 under his advice due to the high hp application and the lack of cold temperatures in Florida. A lot of oil specs that the manufactures put out there have one thing in mind, mpg and CAFE standards.
#35
#36
#38