Machine Lubricant Analyst (MLA) Level II –
Full Mock Examination Newest Updated
2025-2026 Practice Questions From Actual
Exams Complete Questions And Correct
Detailed Answers (Expert Verified Exam)
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1. Which lubricant property is the best indicator of a lubricant's resistance to
flow under changing temperatures?
A. Flash point
B. Pour point
C. Viscosity Index
D. Acid Number
Answer: C. Viscosity Index
The Viscosity Index (VI) measures how much a lubricant's viscosity changes with
temperature. A higher VI indicates more consistent lubrication over a wider
temperature range.
2. What is the primary objective of an oil analysis program?
A. Increase oil consumption
B. Reduce lubricant cost only
C. Detect machine and lubricant condition early
D. Determine machine speed
,Answer: C. Detect machine and lubricant condition early
Oil analysis is primarily used for predictive maintenance, identifying wear,
contamination, and lubricant degradation before failures occur.
3. Which contamination source most commonly introduces silicon into
lubricating oil?
A. Coolant leak
B. Dust ingestion
C. Fuel dilution
D. Oxidation
Answer: B. Dust ingestion
High silicon concentrations usually indicate airborne dirt contamination entering
the lubrication system through poor seals or filtration.
4. Which lubricant additive primarily prevents metal-to-metal contact during
boundary lubrication?
A. Pour point depressant
B. Extreme pressure additive
C. Dye
D. Antifoam additive
Answer: B. Extreme pressure additive
Extreme Pressure (EP) additives chemically react under heavy loads to protect
contacting surfaces from severe wear.
5. What does ISO VG represent?
A. Oil purity classification
B. Grease consistency
C. Lubricant viscosity grade
,D. Oxidation level
Answer: C. Lubricant viscosity grade
The ISO Viscosity Grade (VG) classifies industrial lubricants according to their
viscosity at 40°C.
6. Which instrument directly measures lubricant viscosity?
A. Ferrograph
B. Viscometer
C. Particle counter
D. Spectrometer
Answer: B. Viscometer
A viscometer measures a lubricant's resistance to flow, an essential property for
lubricant selection and condition monitoring.
7. Water contamination in lubricating oil primarily causes:
A. Increased viscosity index
B. Improved oxidation resistance
C. Corrosion and additive depletion
D. Better film strength
Answer: C. Corrosion and additive depletion
Water promotes corrosion, accelerates oxidation, reduces lubricant film strength,
and depletes critical additives.
8. Which ASTM test measures acid number?
A. ASTM D445
B. ASTM D664
C. ASTM D92
, D. ASTM D1500
Answer: B. ASTM D664
ASTM D664 determines the Total Acid Number (TAN), indicating lubricant
oxidation and degradation.
9. Which wear mechanism occurs when two metal surfaces weld
microscopically together?
A. Corrosive wear
B. Adhesive wear
C. Abrasive wear
D. Cavitation
Answer: B. Adhesive wear
In adhesive wear, microscopic junctions form between metal surfaces and tear
away material during sliding.
10.Which lubricant property determines ease of pumpability at low
temperatures?
A. Flash point
B. Pour point
C. TAN
D. Demulsibility
Answer: B. Pour point
The pour point indicates the lowest temperature at which a lubricant remains
fluid enough to flow.
11.Which additive improves oxidation resistance?
A. Antioxidant
B. Dye
Full Mock Examination Newest Updated
2025-2026 Practice Questions From Actual
Exams Complete Questions And Correct
Detailed Answers (Expert Verified Exam)
|Already Graded A+ Instant Download Pdf
1. Which lubricant property is the best indicator of a lubricant's resistance to
flow under changing temperatures?
A. Flash point
B. Pour point
C. Viscosity Index
D. Acid Number
Answer: C. Viscosity Index
The Viscosity Index (VI) measures how much a lubricant's viscosity changes with
temperature. A higher VI indicates more consistent lubrication over a wider
temperature range.
2. What is the primary objective of an oil analysis program?
A. Increase oil consumption
B. Reduce lubricant cost only
C. Detect machine and lubricant condition early
D. Determine machine speed
,Answer: C. Detect machine and lubricant condition early
Oil analysis is primarily used for predictive maintenance, identifying wear,
contamination, and lubricant degradation before failures occur.
3. Which contamination source most commonly introduces silicon into
lubricating oil?
A. Coolant leak
B. Dust ingestion
C. Fuel dilution
D. Oxidation
Answer: B. Dust ingestion
High silicon concentrations usually indicate airborne dirt contamination entering
the lubrication system through poor seals or filtration.
4. Which lubricant additive primarily prevents metal-to-metal contact during
boundary lubrication?
A. Pour point depressant
B. Extreme pressure additive
C. Dye
D. Antifoam additive
Answer: B. Extreme pressure additive
Extreme Pressure (EP) additives chemically react under heavy loads to protect
contacting surfaces from severe wear.
5. What does ISO VG represent?
A. Oil purity classification
B. Grease consistency
C. Lubricant viscosity grade
,D. Oxidation level
Answer: C. Lubricant viscosity grade
The ISO Viscosity Grade (VG) classifies industrial lubricants according to their
viscosity at 40°C.
6. Which instrument directly measures lubricant viscosity?
A. Ferrograph
B. Viscometer
C. Particle counter
D. Spectrometer
Answer: B. Viscometer
A viscometer measures a lubricant's resistance to flow, an essential property for
lubricant selection and condition monitoring.
7. Water contamination in lubricating oil primarily causes:
A. Increased viscosity index
B. Improved oxidation resistance
C. Corrosion and additive depletion
D. Better film strength
Answer: C. Corrosion and additive depletion
Water promotes corrosion, accelerates oxidation, reduces lubricant film strength,
and depletes critical additives.
8. Which ASTM test measures acid number?
A. ASTM D445
B. ASTM D664
C. ASTM D92
, D. ASTM D1500
Answer: B. ASTM D664
ASTM D664 determines the Total Acid Number (TAN), indicating lubricant
oxidation and degradation.
9. Which wear mechanism occurs when two metal surfaces weld
microscopically together?
A. Corrosive wear
B. Adhesive wear
C. Abrasive wear
D. Cavitation
Answer: B. Adhesive wear
In adhesive wear, microscopic junctions form between metal surfaces and tear
away material during sliding.
10.Which lubricant property determines ease of pumpability at low
temperatures?
A. Flash point
B. Pour point
C. TAN
D. Demulsibility
Answer: B. Pour point
The pour point indicates the lowest temperature at which a lubricant remains
fluid enough to flow.
11.Which additive improves oxidation resistance?
A. Antioxidant
B. Dye
