The article provides some information directly from synthetic manufactures (Redline, Amsoil, Syntec, etc) but they don't all agree on everything. It explains how and why synthetic oil got a negative reputation and how it is different now. It also provides some reasons why auto manufacturers still recommend 3,000 miles changes (My synopsis: Due to warranty concerns manufactures like to have the opportunity to periodically inspect the cars). The bottom line is that synthetic oils are always superior to petroleum oils; however, under normal driving conditions the difference may not be noticeable. Synthetics maintain their chemical properties at much more extreme temperatures (above 400 degrees and below -30 degrees), but how often are then conditions seen? Using them can be beneficial if an engine failure is experience. If a motor overheats, for example, a synthetic oil will provide better protection. Is it possible that some of the differing opinions on drain interval are a result of the difference between Group III and Group IV synthetics?
Great Post BTW.
But "dealers wanting to inspect their cars" I don't believe. I'd call your dealer and ask them what oil they use for changes. You'll find the dealer is using bulk oil in big drums and it may or may not meet the specs required for you vehicle. Remember all they care about is getting you past the warranty and making $$$. Toyota Dealer around here uses 10W-30 Castrol, nothing wrong with that but Toyota reccomends 5W-30 for all temps and their new cars and a 5w generally will give you better start up protection and since that's when the majority of engine wear happens why not use a 5w then? the answer is COST, they save a
by using a 10w instead of a 5w. They buy from suppliers just like any other mechanic would. Recently Volkswagen dealers got in hot water for not using VW spec oil , which is a 40 wt, in their 1.8T motors. They were having some serious engine problems and some failures because of it. Don't assume your dealer knows best. Their a business just like anyone else.
There is a lot of confusion and in my research I learn new stuff all the time.
