First of all, I need to make it abundantly clear that I am not speaking of "Miracle Oil Additives" such as Duralube, Prolong and the like, when I refer to oil additives. I am speaking of the additives that are in your oil right from the original bottle that you pulled off the shelf.
Many people swear by these "extra" Miracle Additives, but I am a firm believer in independent lab results. Every independent test I've seen regarding special oil additives such as those mentioned above has given no indication that they provide ANY measure of increased engine protection. In fact, in some cases they may even increase engine wear.
However, this is a whole other story that deserves a complete article. So, for the sake of remaining on topic, I am going to return to the article at hand and leave you to study this oil additive issue a little further on your own.
It is true that the additives in many oils begin breaking down after only a few thousand miles. What needs to be recognized is that there are different quality "grades" of additives just as there are different quality grades of just about any other product that you buy. There are also different combinations of additives that tend to work for better and for longer when combined than when used individually.
Making a blanket statement that additives in oil die after only 2 to 3,000 miles is like saying that automobile tires will only last for 30,000 miles. To be sure, there are plenty of tires on the market that can only last for 30,000 miles, and then they're toast. But, there are many tires on the market nowadays that will last over 75,000 miles.
The same scenario holds true for motor oils. Many oil companies are using the same additives in their oils as all of the other companies because they are cheap. That's why the oil costs less. You get what you pay for. If they were willing to spend the money on top-quality additive packages for their oils, every synthetic on the market would be recommended for extended drain intervals, and they would all be more expensive. The technology has been around for years. The problem is that oil companies make more money selling a cheaper grade oil and making sure that you change it more often.
1. VISCOSITY RETENTION -- Shear stable viscosity index improvers help premium synthetic motor oils maintain their viscosity in the range appropriate to each grade over extended drain use. Conventional oils formulated with easily sheared viscosity index improvers often drop out of viscosity specification relatively quickly -- sometimes even before the end of a 3,000-mile oil drain interval. Viscosity loss leaves oils incapable of protecting engines from metal to metal contact and wear in high temperatures.
NOTE: It was mentioned earlier that petroleum oils tend to thicken due to burn-off. The statement above is not contradictory to that. It just indicates that petroleum oil is vulnerable to two opposing types of breakdown, which, in the end, render the oil basically useless for lubrication purposes.
2. CONTAMINANT CONTROL -- Dispersants keep contaminants, including combustion by-products, suspended in oil. The rate of dispersant depletion depends on the motor oil's additive treat- rate and the oil's contaminant load. Premium synthetic motor oils are formulated with high additive treat rates specifically to allow extended drain intervals.
3. ACID CONTROL -- Total Base Number (TBN) describes the acid neutralization ability of an oil, with higher TBN oils providing longer lasting acid neutralization. Most passenger car motor oils are formulated with TBN of 5 to 7. Many synthetic motor oils are formulated with 9-11 TBN or higher. The result: longer and better acid neutralization capability allowing for extended drain use.
---------------------------------------------------------------- Excerpted with Permission from "The Motor Oil Bible" eBook Copyright 2000 Michael Kaufman ("The Motor Oil Bible" Author) Download it from: http://www.motor-oil-bible.com ---------------------------------------------------------------
Part 2 Motor Oil Breakdown What really Causes It? - Part 4: How Does Oil Contamination Occur?