Drain valves versus plugs versus suction

[Larry C Leung]

You forgot to mention the acidification of the oil due to the combustion
products of water, H2SO4 and CO2 in the crankcase. IF the oil doesn't
regularly get warm enough to boil off the water, it combines with the
other combustion gases to produce various acids. The acids will only form
in the presence of water (acid is simply a dis-sociation of water, as are
bases), so if there is water in the crankcase (also a byproduct of
combustion), from frequent short trips, then you would need to change the
oil to fight acid build up.

LL - NY

On Mon, 5 Nov 2001 10:18:38 -0800 "Darringer, Chris"
<Chris.Darringer at schwab.com> writes:
>I believe there are two separate things happening to your oil over
>time.
>The first is the build up of contamination in the form of particles
>(small
>bits of metal, dirt, etc.).  A filter's job is to reduce this form of
>contamination.  The second is reduced viscocity that comes with high
>temperatures.  The components of oil are chemically altered in a way
>that
>slowly reduces their ability to lubricate.  The oil is also a
>detergent, so
>it is acumulating lots of other contamination in solution.  A filter
>does
>little, if anything, in reversing these effects.  The only way to
>eliminate
>this second kind of contamination is through an oil change.
>
>If you spend three days at the track (with fresh oil and a filter)
>cooking
>your oil at 130 degrees, I would guess that you have reduced its
>viscosity
>considerably without introducing too much more fiter-able
>contamination.  In
>this kind of scenario, it might make sense to just change the oil.  (I
>would
>change the filter too, though - just a little extra time and money).
>
>Chris
>'90 80q
>
>> Good point here Javad.  As with any system using a filter, the
>substance
>> being filtered doesnt need to be changed as often as the filter
>does.  The
>> main reason for the filter being, keeping the substance being
>circulated
>> cleaner.  Changing the oil more than the filter certainly wont hurt
>> anything
>> as long as your getting the filter changed at the correct intervals,
>but
>> techinically your doing it backwards. :)