forum readers...I dont use the oil in this article since the dearship CASTROL SYN does mine but I thought the intelectual information on oil change intervals was one to share..... On a humurous note...cant AUDI give me a phone book oil filter similiar to my phone book air filter :-)

"AMSOIL has been in business since 1972. It's interesting how
some things have not changed at all during that time.
Thirty years ago, oil companies and vehicle manufacturers
were recommending 2,000 to 3,000 mile oil drain intervals.
Today, the auto manufacturers have increased their drain
recommendations significantly. But despite the improvement
in motor oils made during these past 30+ years, and despite
the fact that the same oils are used in Europe with much
longer drain intervals, oil companies here in the U.S. are
still promoting 3,000 mile drain intervals.

According to a feature article in Lubes & Greases magazine,
that represents the unneeded production of 300 million to
400 million gallons of engine oil every year! Who pays for
all the unneeded motor oil? It's the motorists who change
oil more often than necessary. And who profits from
producing all this unneeded motor oil? The oil companies
who continue to recommend frequent oil changes!

The article was written by David McFall, past president of
the American Petroleum Institute (API) and Automotive Editor
for Lubes & Greases magazine. He minces no words in
questioning the motives of oil companies, asking why their
oils can be used for 10,000 miles in European vehicles while
being recommended for only 3,000 miles here in the United
States. Most of us already know the answer to that
question. The oil companies don't want to see their market
cut by at least half by extending drain intervals. They'll
stick to their 3,000 mile drain recommendations as long as
American consumers will keep buying into it, at an estimated
annual cost of $1.5 billion, according to McFall.

Oil specifications and drain recommendations in Europe are
controlled by the vehicle manufacturers, with the oil
companies having less influence than here in the U.S.
Because of higher costs, Europeans are careful about wasting
energy. They are also very environmentally aware. They
would not put with the cost, waste, and environmental
effects of changing their oil very 3,000 miles. They are
very aware of the improved performance synthetic motor oils
provide. To illustrate how the performance of synthetic
oils are appreciated, take note of what follows.

Owners of Mercedes-Benz automobiles in the U.S. were
recently awarded a $32 million settlement because they were
not informed they should use synthetic motor oil. Mercedes
utilizes a system designed to help owners lower maintenance
costs and reduce the adverse environmental impact of used
motor oil. The system extends drain intervals to when the
oil actually needs to be changed, rather than at set
predetermined intervals. They start with 10,000 mile drains
and push them up to 20,000 miles, using synthetic motor
oils!

The problem occurred because these U.S. owners were told to
use conventional motor oils, which could not stand up to
those extended drain intervals. According to the suit, this
promoted more engine wear than if they had been using the
originally specified synthetic oil. Now if that isn't a
testimonial as to the superior performance of synthetic
motor oils, I don't know what is. Thirty-two million
dollars is a tidy sum to pay for increasing engine wear, but
the company did not dispute the fact that the drain
intervals determined by their system were too long for
conventional oils.

McFall's article singled out AMSOIL as the only oil company
actually recommending extended drain intervals. He notes
that the other oil companies either don't make drain
recommendations or stick with their 3,000 mile
recommendation. Consumers must refer to their owners
manuals, which almost always recommend more miles between
oil changes than 3,000 miles for normal operation, or they
can listen to their car dealers or oil change specialists,
who push frequent oil changes to keep their cash registers
ringing.

Mercedes-Benz should be commended for specifying synthetic
lubricants for their superior performance and for extending
drains to minimize the adverse effects of used motor oil on
the environment. As time goes on, there will be an
increasing number of companies who will do the same. But
that won't happen if the oil industry can do the same. They
are actively working to keep the status quo, promoting many
more oil changes than necessary, wasting precious resources,
and creating the need to dispose of more pollutants in the
form of used motor oil.

AMSOIL coined the term "extended drain intervals" back in
the early days of the company. We were the pioneer in
extending drains, producing synthetic lubricants that
performed well beyond what anyone thought possible. Today,
like in this article by McFall, we are recognized as the
leaders in producing extended drain lubricants. Our success
proves the world is ready for our products. There is no
doubt they are needed more today than ever."
amsoil rep.

 

essentially.....synthetic oil lasts longer...

 

Is it damaging to add synthetic oil after adding regular oil? Are there any effects on the engine?