30,000 mile oil

[Mike Arman]

Noticing a buzz on the list about 30,000 miles between oil changes . . .

This isn't new, and in fact it comes up every few years as a "great new
idea", which separates you from your money by keeping you from wasting it
with someone else (dumb oil companies and car manufacturers who insist you
need an oil change every 5,000 miles) by convincing you to waste it with a
different someone else (dumb vendors of trick oil filters, etc.)

If you look around, you can find oil filter cannisters that use a roll of
toilet tissue as the filter element. Supposedly, the vastly greater surface
area of a roll of Coronet or Downy or whatever means you will trap all the
nasties instead of some of the nasties (as the vastly inferior oil filters
supplied by fly-by-night scam artists like Bosch and Mann), which means you
can extend your oil change interval to 50,000 miles thus helping save the
whales or something. Replacement elements are as far away as your local
7-11, and are half a dollar.

Now here's the inside story on oil, and why you need regular oil changes:

1) Oil is supposed to lubricate. (duh.) Oil does this through the action of
what is known as "long-chain polymers", which resemble long strands of
spaghetti. (Obvously much smaller, though, and definitely less tasty.) As
the engine runs, heat and the pressure of the bearings breaks down these
long chains, so the lubricating properties of the oil deteriorate with use.
The harder you run the engine, the more quickly the oil deteriorates.
Synthetic oils (and to a lesser extent, the various blends of dino and
synthetic) are "tougher", and the chains take longer to break down. This
means they will retain their lubricating properties longer than dino oil,
and at somewhat higher temperatures. The oil filter has NOTHING to do with
this. To restore the lubricating properties of new oil, you need to drain
out the old, tired oil and fill with new oil.

2) The oil is the "garbage disposal system" of the engine - various
chemicals and some amount of water and water vapor are part of the
combustion cycle of the internal combustion engine. Another chemical is
sulfur, and this finds its way into the oil (some is already there), where
it mixes with moisture to make dilute sulfuric acid, right in the oil pan
of your precious engine. Oils have various additives which (among other
things), attempt to neutralize the various chemical nasties which result
from the normal operation of the engine. If you leave the same oil in
"forever", eventually, these chemicals are used up since they exist in
finite amounts while the engine keeps adding more and more of the stuff
these chemicals are supposed to neutralize, eventually overwhelming them.
There are also anti-foaming agents, and these don't last forever, either.
To restore the trick chemistry, you need to drain out the old, dirty oil,
and fill with new oil. The filter does trap some amount of sludge, but
cannot restore the chemistry.

3. The oil carries off particulate matter, and it is trapped in the filter.
This particulate matter is bits of carbon (from combustion), sludge (water
plus some of the above chemicals), flakes of metal, tiny bits of sand
either from the engine casting itself or which goes through the K&N air
filter and gets pulverized in the top end, and most but not all of it goes
out the exhaust, lint from the rag you used to check the oil, and so forth.
This is the function of the oil filter - to remove PARTICULATE matter, and
as much sludge and other goo as possible. Note that the oil filter is a
mechanical device, and does not affect the chemistry or lubricating
properties of the oil in any significant way!

The oil filter addresses only ONE aspect of oil usage - it takes out the
rocks and dinosaur bones. While it is vitally important, no oil filter on
earth will address or even affect all the other problems, or make the paint
shine, or reduce your 0-60 times by 20%, or make your engine last forever
with zero maintenance.

Change the oil regularly! On cars that live in damp climates and are driven
infrequently, change it more often. On cars that are driven hard, change it
more often. On cars that are driven in dry, dusty climates, change it more
often.

Here are the numbers: Oil change every 30,000 miles at the jiffy lube
(ugh!) means five oil changes in 150,000 miles - (we presume the engine
came with oil already in it at 0 miles). At $20 per oil change, that's $100.

Oil change every 5,000 miles means 29 oil changes in 150,000 miles, at $20
each, total $580.

$480 is cheap insurance for 150,000 miles of engine life! With oil changes
every 5,000 miles, the cost of new oil is about 1/3 of a cent per mile
driven. If you can't afford that, you need to break out the roller skates!

Remember - oil is cheap, engines aren't. How much does the head cost on a
20 valve I-5? Now how much to rebuild the bottom end?

Remember also - there are lots of scams out there, preying on the ignorance
of worried people. The least worst of these scams do no harm (like magnets
on the fuel line), and only cost money. There are some really nasty ones,
too. My favorite is the Freon replacement which is mostly propane, and is
explosive in an accident when the leaking propane hits the hot exhaust
manifold. . . .

Change your oil!

Best Regards,

Mike Arman