The slides, written out
AI-drawn illustration. Simplified to explain the idea, not to scale.
Slide 1 · UNDERSTANDING
UNDERSTANDING
LUBE OIL
ANALYSIS
What Wear Metals
and Insolubles Are
Really Telling You
OIL ANALYSIS REPORT
Slide 2 · WEAR METALS
WEAR METALS:
THE ENGINE'S EARLY
WARNING SYSTEM
Wear metals in used oil show which engine parts are
wearing — long before problems become critical.
1 IRON (Fe)
USUALLY INDICATES
• Piston rings
• Cylinder liners
• Piston skirts (steel)
• Gear train / timing gears
KEY CHECK
Monitor trend versus
previous samples and
engine baseline.
2 COPPER (Cu)
USUALLY INDICATES
• Bearing overlays
• Bronze bushes
• Thrust washers
• Oil cooler materials
• Running-in wear
KEY CHECK
Verify sampling point
and also consider other
legitimate sources.
3 TIN (Sn)
USUALLY INDICATES
• White-metal bearing
overlay wear
• Thrust bearing pads
• Crosshead / slipper
bearings
KEY CHECK
Rising tin, especially
with antimony, points
to bearing wear.
4 ANTIMONY (Sb)
USUALLY INDICATES
• Bearing alloy involvement
• White-metal overlay wear
• (Additive sources also
possible)
KEY CHECK
Check trend along with
tin and copper for a
clearer picture.
TREND ANALYSIS IS MORE VALUABLE
THAN ANY SINGLE PPM VALUE.
Slide 3 · WHEN SILICON APPEARS
WHEN SILICON APPEARS:
FIND THE SOURCE FAST
Elevated silicon (Si) indicates hard particulate contamination.
Use aluminium (Al) results and engine history to identify the source.
ELEVATED
SILICON (Si)
IS ALUMINIUM (Al)
ALSO ELEVATED?
YES
NO
POSSIBLE
CAT FINES
Catalytic fines from fuel.
CHECK:
Fuel analysis (Al + Si)
Purifier efficiency & operation
Settling tank management
Fuel quality & changeover
POSSIBLE
DUST INGRESS
Airborne dirt entering
the engine.
CHECK:
Air filters condition
Intake seals & ducting
Turbocharger condition
Crankcase breather system
SILICON IS ABRASIVE
It accelerates ring, liner and bearing wear.
Identify the source and act early.
Slide 4 · WHAT INSOLUBLES REVEAL
WHAT INSOLUBLES REVEAL
Two insoluble measurements. Two insights.
Together, they tell the real story of your oil.
n-PENTANE INSOLUBLES
TOLUENE INSOLUBLES
MEASURES:
• Soot (carbon)
• Sludge / oxidation products
• Wear debris
• Dirt contamination
• Other insoluble materials
MEASURES:
The more refractory
insoluble fraction
remaining after
dissolution of many
organic degradation
products.
TYPICAL MEANING:
Rising values indicate
increasing contamination
loading and soot build-up.
TYPICAL MEANING:
High values may indicate:
• Wear debris
• Dirt ingress
• Poor contaminant removal
• Ineffective purification
CHIEF ENGINEER ACTION CHECKLIST
Review trend history – don't react to a single report.
Check purifier performance and sludge discharge frequency.
Inspect filters and differential pressure.
Verify combustion quality and injection condition.
Compare results against OEM limits and recommendations.
DON'T CHASE SINGLE NUMBERS.
TRACK TRENDS. CONFIRM CAUSES. ACT EARLY.
Drafted by SailR from our daily lessons. AI-drawn illustration. Simplified to explain the idea, not to scale. Last updated 19 Oct 2026.
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