MACHINE LUBRICANT ANALYST (MLA) LEVEL II –
FULL MOCK EXAMINATION QUESTIONS AND
CORRECT ANSWERS (VERIFIED ANSWERS)
PLUS RATIONALES 2026 Q&A | INSTANT
DOWNLOAD PDF
Core Domains
• Lubricant Roles and Functions
• Oil Sampling – Equipment, Methods, and Process Management
• Lubricant Health Monitoring – Degradation Mechanisms and Additive
Depletion
• Lubricant Contamination Measurement and Control
• Wear Debris Monitoring and Analysis
• Oil Analysis Maintenance Strategies and Condition-Based Maintenance
• Lubrication Regimes and Tribology Fundamentals
• Regulatory Standards and Compliance (ISO 18436-4, ASTM)
• Ethics, Professional Standards, and Program Management
Introduction
This comprehensive mock examination is designed to rigorously assess the
knowledge and practical competencies required for the Machine Lubricant Analyst
(MLA) Level II certification. The exam evaluates a candidate’s proficiency in applying
oil analysis for machine condition monitoring, lubricant health assessment, and
precision troubleshooting. It encompasses foundational lubrication theory,
contamination control strategies, wear debris interpretation, and the implementation
of condition-based maintenance programs. The assessment consists of one hundred
,multiple-choice questions that blend theoretical understanding with real-world,
scenario-based decision-making. Candidates are expected to demonstrate critical
thinking, data interpretation skills, and adherence to industry standards and ethical
practices essential for effective lubrication program management.
SECTION ONE: QUESTIONS 1–100
Question 1
Which of the following lubrication regimes is characterized by a full fluid film that
completely separates two moving surfaces, with the film pressure generated by the
motion of the surfaces themselves?
A. Boundary lubrication
B. Mixed lubrication
C. Hydrodynamic lubrication
D. Elastohydrodynamic lubrication
C. Hydrodynamic lubrication
RATIONALE: Hydrodynamic lubrication occurs when a converging wedge of fluid
is drawn between two moving surfaces, generating sufficient pressure to support the
load without surface contact. This regime is dependent on viscosity, relative velocity,
and load. Boundary lubrication involves surface contact and relies on additive films,
while mixed lubrication is a transition state. Elastohydrodynamic lubrication occurs
in non-conformal contacts like gears and rolling element bearings.
Question 2
According to ISO 4406, the cleanliness code is reported as a three-number set. What
do these three numbers represent?
,A. The number of particles greater than 4, 6, and 14 micrometers per milliliter
B. The ISO cleanliness code levels for particles of 2, 5, and 15 micrometers
C. The particle count ranges for sizes 4, 6, and 14 micrometers expressed as code
numbers
D. The total number of particles in three different size ranges per 100 milliliters
C. The particle count ranges for sizes 4, 6, and 14 micrometers expressed as
code numbers
RATIONALE: ISO 4406 uses a three-number code where each number
corresponds to a range of particle counts for sizes ≥4 µm(c), ≥6 µm(c), and ≥14
µm(c). The code numbers are derived from a logarithmic scale, with each increment
representing a doubling of particle concentration. Options A and D describe actual
counts or misinterpret the reporting method; B uses incorrect size thresholds.
Question 3
A routine oil sample from a gearbox shows a sudden increase in iron (Fe)
concentration by 150 ppm above baseline, while copper (Cu) and lead (Pb) remain
stable. Viscosity and water content are within normal limits. Which is the most likely
interpretation?
A. Normal adhesive wear from the gear teeth meshing
B. Severe corrosive wear caused by acid formation
C. Abrasive wear from ingested contaminants
D. Catastrophic bearing failure
A. Normal adhesive wear from the gear teeth meshing
RATIONALE: In gearboxes, iron is the primary component of gear teeth. A gradual
or moderate increase in iron without corresponding increases in bearing metals
(copper, lead) or contaminants typically indicates normal adhesive wear from gear
meshing. Corrosive wear would show multiple metal increases and acid number
elevation. Abrasive wear would present with elevated silicon and other
, contaminants. Catastrophic bearing failure would show sharp spikes in bearing
metals.
Question 4
Which ASTM standard is specifically used for the multielement determination of
wear metals, contaminants, and additive elements in lubricating oils by inductively
coupled plasma atomic emission spectrometry (ICP-AES)?
A. ASTM D445
B. ASTM D5185
C. ASTM D2272
D. ASTM D974
B. ASTM D5185
RATIONALE: ASTM D5185 is the standard test method for the determination of
additive elements, wear metals, and contaminants in used and unused lubricating
oils by ICP-AES. ASTM D445 measures kinematic viscosity, ASTM D2272 measures
oxidation stability via the RPVOT test, and ASTM D974 measures acid number by
color-indicator titration.
Question 5
In the context of oil analysis, what is the primary purpose of the rotating pressure
vessel oxidation test (RPVOT)?
A. To measure the viscosity index of the oil
B. To determine the remaining useful life of the oil's oxidation inhibitors
C. To quantify the total acid number (TAN) of the oil
D. To detect the presence of fuel dilution in the oil
B. To determine the remaining useful life of the oil's oxidation inhibitors
FULL MOCK EXAMINATION QUESTIONS AND
CORRECT ANSWERS (VERIFIED ANSWERS)
PLUS RATIONALES 2026 Q&A | INSTANT
DOWNLOAD PDF
Core Domains
• Lubricant Roles and Functions
• Oil Sampling – Equipment, Methods, and Process Management
• Lubricant Health Monitoring – Degradation Mechanisms and Additive
Depletion
• Lubricant Contamination Measurement and Control
• Wear Debris Monitoring and Analysis
• Oil Analysis Maintenance Strategies and Condition-Based Maintenance
• Lubrication Regimes and Tribology Fundamentals
• Regulatory Standards and Compliance (ISO 18436-4, ASTM)
• Ethics, Professional Standards, and Program Management
Introduction
This comprehensive mock examination is designed to rigorously assess the
knowledge and practical competencies required for the Machine Lubricant Analyst
(MLA) Level II certification. The exam evaluates a candidate’s proficiency in applying
oil analysis for machine condition monitoring, lubricant health assessment, and
precision troubleshooting. It encompasses foundational lubrication theory,
contamination control strategies, wear debris interpretation, and the implementation
of condition-based maintenance programs. The assessment consists of one hundred
,multiple-choice questions that blend theoretical understanding with real-world,
scenario-based decision-making. Candidates are expected to demonstrate critical
thinking, data interpretation skills, and adherence to industry standards and ethical
practices essential for effective lubrication program management.
SECTION ONE: QUESTIONS 1–100
Question 1
Which of the following lubrication regimes is characterized by a full fluid film that
completely separates two moving surfaces, with the film pressure generated by the
motion of the surfaces themselves?
A. Boundary lubrication
B. Mixed lubrication
C. Hydrodynamic lubrication
D. Elastohydrodynamic lubrication
C. Hydrodynamic lubrication
RATIONALE: Hydrodynamic lubrication occurs when a converging wedge of fluid
is drawn between two moving surfaces, generating sufficient pressure to support the
load without surface contact. This regime is dependent on viscosity, relative velocity,
and load. Boundary lubrication involves surface contact and relies on additive films,
while mixed lubrication is a transition state. Elastohydrodynamic lubrication occurs
in non-conformal contacts like gears and rolling element bearings.
Question 2
According to ISO 4406, the cleanliness code is reported as a three-number set. What
do these three numbers represent?
,A. The number of particles greater than 4, 6, and 14 micrometers per milliliter
B. The ISO cleanliness code levels for particles of 2, 5, and 15 micrometers
C. The particle count ranges for sizes 4, 6, and 14 micrometers expressed as code
numbers
D. The total number of particles in three different size ranges per 100 milliliters
C. The particle count ranges for sizes 4, 6, and 14 micrometers expressed as
code numbers
RATIONALE: ISO 4406 uses a three-number code where each number
corresponds to a range of particle counts for sizes ≥4 µm(c), ≥6 µm(c), and ≥14
µm(c). The code numbers are derived from a logarithmic scale, with each increment
representing a doubling of particle concentration. Options A and D describe actual
counts or misinterpret the reporting method; B uses incorrect size thresholds.
Question 3
A routine oil sample from a gearbox shows a sudden increase in iron (Fe)
concentration by 150 ppm above baseline, while copper (Cu) and lead (Pb) remain
stable. Viscosity and water content are within normal limits. Which is the most likely
interpretation?
A. Normal adhesive wear from the gear teeth meshing
B. Severe corrosive wear caused by acid formation
C. Abrasive wear from ingested contaminants
D. Catastrophic bearing failure
A. Normal adhesive wear from the gear teeth meshing
RATIONALE: In gearboxes, iron is the primary component of gear teeth. A gradual
or moderate increase in iron without corresponding increases in bearing metals
(copper, lead) or contaminants typically indicates normal adhesive wear from gear
meshing. Corrosive wear would show multiple metal increases and acid number
elevation. Abrasive wear would present with elevated silicon and other
, contaminants. Catastrophic bearing failure would show sharp spikes in bearing
metals.
Question 4
Which ASTM standard is specifically used for the multielement determination of
wear metals, contaminants, and additive elements in lubricating oils by inductively
coupled plasma atomic emission spectrometry (ICP-AES)?
A. ASTM D445
B. ASTM D5185
C. ASTM D2272
D. ASTM D974
B. ASTM D5185
RATIONALE: ASTM D5185 is the standard test method for the determination of
additive elements, wear metals, and contaminants in used and unused lubricating
oils by ICP-AES. ASTM D445 measures kinematic viscosity, ASTM D2272 measures
oxidation stability via the RPVOT test, and ASTM D974 measures acid number by
color-indicator titration.
Question 5
In the context of oil analysis, what is the primary purpose of the rotating pressure
vessel oxidation test (RPVOT)?
A. To measure the viscosity index of the oil
B. To determine the remaining useful life of the oil's oxidation inhibitors
C. To quantify the total acid number (TAN) of the oil
D. To detect the presence of fuel dilution in the oil
B. To determine the remaining useful life of the oil's oxidation inhibitors
