by Ed Newman
AMSOIL Director of Advertising
article appeared in National Oil & Lube News, April 2010
AVE YOU EVER MET PEOPLE who have simplistic answers to complex questions
and never want to take time to think a little more deeply about the subject?
To be honest with you, I think we all fit that description from time to
time. Many issues are so complicated that we just don’t have the time
to really study them in depth. So we opt out for the simple answer. For
example, let’s talk about motor oil consumption.
Ever had a car where you had to top off your oil now and then? Who
hasn’t? In my case, I always assumed that this was due to the
oil’s volatility. That is, when the engine was hot, the oil’s
lighter molecules would vaporize.
I once attended two days of training at a quick lube (part of a major oil
company chain) wherein they showed how their conventional oil lost up to 30
percent and their synthetic only 12 percent in a volatility test. It sank
home the message I’d already adopted, that synthetics were more
resistant to oil loss than conventional oils. While this may be true to a
large extent it is not the end of the discussion.
I saw a Technical Service Bulletin called The Reasons for Motor Oil
Consumption, and seven pages later I could no longer stand on my simple one
sentence answer to the problem. The problem of abnormal oil usage is far
more complicated and, in fact, most of the causes are mechanical, not
lubricant related at all.
Here are just the first of 40 explanations for oil consumption: External Oil
“Some of the many points where external oil leaks may occur include,
oil lines, crankcase drain plug, oil pan gasket, valve cover gaskets, oil
pump gasket, fuel pump gasket, timing case cover and camshaft bearing seal.
No possible source of leakage should be neglected because even a very small
leak can cause extremely high oil consumption. For example, it has been
estimated that a leak of one drop of oil every 20 feet is approximately
equal to a loss of one quart of oil every 100 miles. One way to check for
external leaks is to road test the vehicle with a large piece of
light-colored cloth tied under the engine. Oil on the cloth will indicate a
leak which should be traced to its source.”
But the list goes on. The problem may be front or rear main bearing seals,
worn or damaged main bearings, worn or damaged connecting rod bearings, worn
or damaged camshaft bearings, worn crankshaft journals, distorted cylinders,
honing abrasive, worn ring grooves, cracked or broken ring lands, problems
with the wrist pins, clogged oil passages, or even unequal tightening of
Item 20 on the list had to do with the radiator, and I initially thought
this was just a bit much. Until I read the explanation. A defective cooling
system can cause overheating of the engine which may result in the
development of localized hot spots in some of the cylinders which can lead
to scuffing and scoring of cylinders, pistons and rings resulting in high
And the list goes on. Dirty oil, too much oil in the crankcase, worn or
broken piston rings, improper valve timing, incorrect oil pressure, piston
slap, internal gasket intake breach, spark knock, aftermarket performance
chips and modifications, lugging engines, inappropriate operation of
overdrive, leaking turbocharger seals, restricted air intakes and fuel
dilution can all contribute in various ways to oil consumption.
In short, few things are as simple as they might initially appear. When all
is said and done, however, even though there may be multiple reasons for oil
loss, in a mechanically sound engine it boils down to one: the volatility
issue. In this, synthetic motor oils make a difference. For this reason, if
your customers’ vehicles are mechanically sound they should be using
synthetics to reduce their oil consumption. Benefits include reduced oil
usage, reduced emissions and improved fuel economy.
Here’s another simple answer that is more complicated than it looks:
the cost of synthetics. People who say synthetic motor oils are too
expensive have often never gone into depth analyzing the real life cycle
costs of a premium synthetic motor oil versus conventional petroleum. The
initial cost appears quite a bit higher, but the life cycle cost is the true
measure. The annual cost of a premium extended drain synthetic is comparable
to or even less than conventional oils these days, and the benefits too
numerous for this short summation. When your customer is driving a vehicle
with a mechanically sound engine, I always recommend a synthetic solution.