Quote Originally Posted by blackshine007
Great point to mention that. If any of ya'll do decide to go longer between oil changes, make sure that royal purple isn't in your crank case. I personally think that it's highly overpriced. I found out that Shell Rotella has zinc in it and I was convinced that (well after my buddy ran it in his turbo car without any problems) it would do well in my vehicles. Shell Rotella 15w40 FTW
Go with the Rotella T 5w40 (as opposed to the normal Rotella). Its indestructable.

Quote Originally Posted by green91
you guys do realize the reason you change your oil isn't because the oil breaks down after 3-5k right? yes synthetics last longer. but the reason for oil changes is because of the carbon contamination due to the combustion process getting into the oil. hence why oil gets darker. synthetics and fossil oils alike suffer this same fate.. so those of you who run synthetics to extend your oil change intervals may actually be doing more harm than good.
Yep, thats why I keep advocating getting your oil analyzed. Not only will it tell you what the actual viscosity of the oil is but it will also tell you the flash point as well as what trace metals or chemicals are in your oil. It costs $22.50 but is worth so much more than that.