Page 1 of 56
MACHINE LUBRICANT ANALYST (MLA) LEVEL II – MOCK
EXAMINATION 2026/2027 COMPLETE (150) CURRENT
TESTING QUESTIONS AND CORRECT ANSWERS WITH
DETAILED RATIONALES.
(MLA)
Prepare effectively for the Machine Lubricant Analyst (MLA) Level II Mock Examination
with this focused practice resource. It supports review of lubricant analysis, oil
condition monitoring, contamination control, wear debris analysis, sampling
techniques, and predictive maintenance principles. Use the material to reinforce your
technical knowledge, practice key concepts, and identify areas that may require
additional study. This resource is suited for lubrication professionals, maintenance
technicians, reliability specialists, and candidates preparing for MLA Level II
certification.
MULTIPLE CHOICE.
DOMAIN I: LUBRICANT ROLES AND FUNCTIONS (Questions 1–6)
Question #1
What is the primary function of additives in lubricants?
A. Additives are only added to oil to make it last longer in storage
B. Enhance existing base oil properties
C. Suppress undesirable base oil properties only
D. Replace the need for base oils
Correct Answer: B
Rationale: The function of additives in lubricants is to enhance existing
base oil properties and, in some cases, suppress undesirable properties.
Additives do not replace base oils but improve their performance.
Question #2
The ISO designation of an oil indicates what?
, Page 2 of 56
A. Viscosity at 40°F
B. Viscosity at 100°F
C. Viscosity at 100°C
D. Viscosity at 40°C
Correct Answer: D
Rationale: The ISO viscosity grade (VG) designation indicates the oil's
viscosity at 40°C (104°F), measured in centistokes (cSt). This is the
international standard for classifying industrial lubricants.
Question #3
Which of the following is NOT a mode of lubricant film condition?
A. Full film lubrication
B. Mixed film lubrication
C. Boundary lubrication
D. Dry lubrication
Correct Answer: D
Rationale: The three modes of lubricant film condition are full film, mixed
film, and boundary lubrication. Dry lubrication is not a recognized lubricant
film condition; it represents a complete absence of lubricant.
Question #4
In the ISO viscosity system, what is the acceptable tolerance range for the
40°C viscosity of an ISO VG oil?
A. ±5 cSt
B. ±5%
C. ±10 cSt
D. ±10%
Correct Answer: D
Rationale: The acceptable tolerance range for the 40°C viscosity in the
ISO viscosity system is ±10%. This means an ISO VG 100 oil can range from
90 to 110 cSt at 40°C.
, Page 3 of 56
Question #5
Which type of base oil would typically have a viscosity index (VI) of around
100?
A. Polyalphaolefin (PAO) synthetic
B. Group I mineral oil
C. Group II mineral oil
D. Ester synthetic
Correct Answer: B
Rationale: Group I mineral oils typically have a viscosity index around 90–
100. Group II oils have VIs of 100–120; PAOs have VIs of 120–150; esters can
have VIs exceeding 140. The VI indicates how much viscosity changes with
temperature.
Question #6
Which of the following is a surface-active additive?
A. Antioxidant
B. Viscosity index improver
C. Anti-wear (AW) additive
D. Pour point depressant
Correct Answer: C
Rationale: Surface-active additives such as anti-wear (AW) and extreme
pressure (EP) additives are polar molecules that adsorb to metal surfaces.
They form a protective film to reduce friction and wear. Antioxidants, VI
improvers, and pour point depressants are bulk-oil active additives.
DOMAIN II: OIL ANALYSIS MAINTENANCE STRATEGIES (Questions 7–12)
Question #7
The most economically beneficial application for condition monitoring by oil
, Page 4 of 56
analysis is when the information is applied to which type of maintenance
strategy?
A. Proactive maintenance
B. Regressive maintenance
C. Predictive maintenance
D. Run-to-failure
Correct Answer: A
Rationale: Proactive maintenance is the most economically beneficial
application because it addresses the root causes of equipment degradation
before failure occurs. Predictive maintenance detects failures as they
develop; run-to-failure is the least cost-effective.
Question #8
Which of the following is an example of proactive use of oil analysis?
A. Wear debris analysis
B. Analytical ferrography
C. Direct read ferrography
D. Contamination analysis
Correct Answer: D
Rationale: Contamination analysis is proactive because it identifies
contaminants (water, particles, fuel, glycol) before they cause damage. Wear
debris analysis is reactive or predictive—it detects damage that has already
occurred.
Question #9
What is the primary goal of preventive maintenance?
A. To repair equipment after failure
B. To perform scheduled maintenance to prevent failures
C. To monitor equipment condition continuously
D. To replace equipment before failure
MACHINE LUBRICANT ANALYST (MLA) LEVEL II – MOCK
EXAMINATION 2026/2027 COMPLETE (150) CURRENT
TESTING QUESTIONS AND CORRECT ANSWERS WITH
DETAILED RATIONALES.
(MLA)
Prepare effectively for the Machine Lubricant Analyst (MLA) Level II Mock Examination
with this focused practice resource. It supports review of lubricant analysis, oil
condition monitoring, contamination control, wear debris analysis, sampling
techniques, and predictive maintenance principles. Use the material to reinforce your
technical knowledge, practice key concepts, and identify areas that may require
additional study. This resource is suited for lubrication professionals, maintenance
technicians, reliability specialists, and candidates preparing for MLA Level II
certification.
MULTIPLE CHOICE.
DOMAIN I: LUBRICANT ROLES AND FUNCTIONS (Questions 1–6)
Question #1
What is the primary function of additives in lubricants?
A. Additives are only added to oil to make it last longer in storage
B. Enhance existing base oil properties
C. Suppress undesirable base oil properties only
D. Replace the need for base oils
Correct Answer: B
Rationale: The function of additives in lubricants is to enhance existing
base oil properties and, in some cases, suppress undesirable properties.
Additives do not replace base oils but improve their performance.
Question #2
The ISO designation of an oil indicates what?
, Page 2 of 56
A. Viscosity at 40°F
B. Viscosity at 100°F
C. Viscosity at 100°C
D. Viscosity at 40°C
Correct Answer: D
Rationale: The ISO viscosity grade (VG) designation indicates the oil's
viscosity at 40°C (104°F), measured in centistokes (cSt). This is the
international standard for classifying industrial lubricants.
Question #3
Which of the following is NOT a mode of lubricant film condition?
A. Full film lubrication
B. Mixed film lubrication
C. Boundary lubrication
D. Dry lubrication
Correct Answer: D
Rationale: The three modes of lubricant film condition are full film, mixed
film, and boundary lubrication. Dry lubrication is not a recognized lubricant
film condition; it represents a complete absence of lubricant.
Question #4
In the ISO viscosity system, what is the acceptable tolerance range for the
40°C viscosity of an ISO VG oil?
A. ±5 cSt
B. ±5%
C. ±10 cSt
D. ±10%
Correct Answer: D
Rationale: The acceptable tolerance range for the 40°C viscosity in the
ISO viscosity system is ±10%. This means an ISO VG 100 oil can range from
90 to 110 cSt at 40°C.
, Page 3 of 56
Question #5
Which type of base oil would typically have a viscosity index (VI) of around
100?
A. Polyalphaolefin (PAO) synthetic
B. Group I mineral oil
C. Group II mineral oil
D. Ester synthetic
Correct Answer: B
Rationale: Group I mineral oils typically have a viscosity index around 90–
100. Group II oils have VIs of 100–120; PAOs have VIs of 120–150; esters can
have VIs exceeding 140. The VI indicates how much viscosity changes with
temperature.
Question #6
Which of the following is a surface-active additive?
A. Antioxidant
B. Viscosity index improver
C. Anti-wear (AW) additive
D. Pour point depressant
Correct Answer: C
Rationale: Surface-active additives such as anti-wear (AW) and extreme
pressure (EP) additives are polar molecules that adsorb to metal surfaces.
They form a protective film to reduce friction and wear. Antioxidants, VI
improvers, and pour point depressants are bulk-oil active additives.
DOMAIN II: OIL ANALYSIS MAINTENANCE STRATEGIES (Questions 7–12)
Question #7
The most economically beneficial application for condition monitoring by oil
, Page 4 of 56
analysis is when the information is applied to which type of maintenance
strategy?
A. Proactive maintenance
B. Regressive maintenance
C. Predictive maintenance
D. Run-to-failure
Correct Answer: A
Rationale: Proactive maintenance is the most economically beneficial
application because it addresses the root causes of equipment degradation
before failure occurs. Predictive maintenance detects failures as they
develop; run-to-failure is the least cost-effective.
Question #8
Which of the following is an example of proactive use of oil analysis?
A. Wear debris analysis
B. Analytical ferrography
C. Direct read ferrography
D. Contamination analysis
Correct Answer: D
Rationale: Contamination analysis is proactive because it identifies
contaminants (water, particles, fuel, glycol) before they cause damage. Wear
debris analysis is reactive or predictive—it detects damage that has already
occurred.
Question #9
What is the primary goal of preventive maintenance?
A. To repair equipment after failure
B. To perform scheduled maintenance to prevent failures
C. To monitor equipment condition continuously
D. To replace equipment before failure
