for those of you who dont feel like reading the whole article...this pretty much sums it up:
"...The major oil companies are some of the richest, most powerful and aggressive corporations in world. They own multi- million dollar research facilities manned by some of the best chemical engineers money can hire. It is probably safe to say that any one of them has the capabilities and resources at hand in marketing, distribution, advertising, research and product development equal to 20 times that of any of the independent additive companies. It therefore stands to reason that if any of these additive products were actu ally capable of improving the capabilities of engine lubricants, the major oil companies would have been able to determine that and to find some way to cash in on it.
Yet of all the oil additives we found, none carried the name or endorsement of any of the major oil producers.
In addition, all of the major vehicle and engine manufacturers spend millions of dollars each year trying to increase the longevity of their products, and millions more paying off warranty claims when their products fail. Again, it only stands to reason that if they thought any of these additives would increase the life or improve the performance of their engines, they would be actively using and selling them - or at least endorsing their use.
Instead, many of them advise against the use of these additives and, in some cases, threaten to void their warranty coverage if such things are found to be used in their products.... "