MAIN
FEATURE
Table showing a summary of disorders detectable using oil analysis
Disorder
Impact
Intervention
High silicon content in
combination with increased
wear
Dust or sand entering the engine
through the air intake system
causing abrasive wear in the
engine
Control of air filtration (filter, hoses,
pipes)
High fuel dilution in
combination with viscosity
drop
The oil loses its viscosity drop
which may cause piston seizure
and wear of the bearings
Check the injection system (injections,
returns, feed pump, injection pump)
Presence of water and/or
antifreeze in the oil
The water and antifreeze have a
corrosive impact on the bearings
and this may lead to a failure of
bearings, leading to the loss of
the engine
The cooling system (head gasket,
cylinder heads, injector seats,
compressor, oil cooler... I should be
checked on its tightness
Increase in soot
concentration combined
with viscosity increase
Carbon matter can cause abrasive
wear on the engine. The increased
viscosity has a negative influence
the lubrication and the fuel
comsumption
Check engine settings (injection, turbo)
and check for obstructed air filter. Loss
of compression may also result in high
soot concentration.
now universally accepted. Oil analysis test
procedures are established and reviewed by
such agencies as the International Organization for Standardization (ISO), the American
Society for Testing and Materials (ASTM) and
the Society of Automotive Engineers (SAE),
and a wide variety of laboratory and personnel certifications has emerged.
Physical Tests
Some of the physical properties tested for and
usually included in analysis of an oil sample
are:
• Coolant forms a gummy substance that
may reduce oil flow. It leads to high oxidation, oil thickening, high acidity, and
engine failure if not corrected.
• Fuel dilution thins oil, lowers lubricating
ability, and might drop oil pressure. This
usually causes higher wear.
• Oxidation measures gums, varnishes and
oxidation products. High oxidation from
oil used too hot or too long can leave
sludge and varnish deposits and thicken
the oil.
• Total base number generally indicates
the acid-neutralizing capacity still in the
16
lubricant.
• Total solids include ash, carbon, lead salts
from gasoline engines, and oil oxidation.
• Viscosity is a measure of oil’s resistance to
flow. Oil may thin due to shear in multiviscosity oils or by dilution with fuel. Oil
may thicken from oxidation when run too
long or too hot. Oil also may thicken from
contamination by coolant, sugar and other
materials
Spectrochemical tests
Selected metallic elements present as microscopic particles suspended in the fluid to be
analyzed are identified and measured in parts
per million by weight.
The analyzed elements are grouped into
three main categories: i.e wear metals,
contaminants and additives. These tests are
done by emission spectroscopy. Though not
exhaustive, the table below table gives an idea
of the sources of chemical elements found in
an oil sample.
The results
Results of the laboratory analysis are typically returned in two to seven days after the
lab receives the sample. Results are returned
to the owner for review. The laboratory may
note when the analysis shows an abnormal
condition and issue a caution or recommendation accordingly as per the diagnosis below.
Cost, Convenience and
return on investment
Cost of oil analysis will vary according to the
laboratory and extent of the analysis. Typical charges are $10 to $70 per analysis. The
expense can easily be justified if it alerts the
owner of a major problem that can be corrected and will help prevent downtime when
the machine is needed.
Several companies have developed oil
analysis kits that make oil analysis convenient. These kits include the sample bottles,
suction pump and tubing, and possibly a preaddressed, postage-paid mailing container.
The reasonable cost and convenience of
oil analysis for use makes it another management tool that should be considered by
anyone wanting to do preventive maintenance.
The return on investment is easily 15 to
every Shilling spent.
.
Lubezine Magazine | July-September 2012