Who was it who mentioned Fram oil filters and dropping oil pressure?

dr_jeff wrote:

>
> Please tell me how a mechanic is supposed to know the organic chemistry,
> metallurgy and engineering in determining how often the oil needs to be
> changed.

That never was the question. Here is the quote

"As a car ages, more frequent changes
might be in order, but that's for a
qualified mechanic to decide on a
case-by-case basis."

Modern oils hold the fine dirt particles that the oil filter do not
remove in suspension. But oil can only hold so much dirt. If you change
oil often enough the oil changes get rid of the dirt. If you don't
change the oil as often them some of the dirt will stay in the engine.
If every oil change you leave some dirt in the engine it adds up. This
does not require a Ph.D. to comprehend. Examining an old car and
determining whether the engines oil needs to be changed more frequently
is not the intractable and difficult proposition that you are making it
out to be.


>
> If very think, chunky oil is coming, obviously, the interval is too
> long. However, please explain what kind of knowledge base a good
> mechanic has that let's him/her determine the proper interval better
> that is better than the one recommended by the car maker.

I have seen plenty of examples where car manufacturers provide
recommendations to mechanics in one form or another to examine the oil
and engine to determine if the oil has been changed as often as it
should be. Typically this sort of advice comes in service bulletins
that are intended to help diagnose engine noises like valve train
clatter. More often than not these descriptions do not go into any
particular detail of how the mechanic is to make such a analysis. It is
assumed that a competent mechanic can tell the difference between a
clean engine and one that is not.

-jim