ICML MLA 1 Certification Exam Questions &
Correct Answers / Latest Verified
Certification Exam Review with Rationales
Question 1
Which is a significant risk of mixing hydraulic oil with gear oil without compatibility
testing?
A. TAN increases immediately
B. Flash point doubles
C. Additives may precipitate, forming sludge and blocking filters
D. The oil separates into layers instantly
Correct Answer
Answer: C
Explanation: Additives from different formulations can react, causing precipitates,
sludge, and filter plugging. This is why compatibility testing and flushing are
essential before conversions.
Question 2
A technician wants to top-up a turbine reservoir with oil from a new drum. The
ambient temperature is 35 °C, and the drum has been stored outdoors, lying on its
side with bungs at 3 and 9 o'clock. What is the main contamination risk?
A. Varnish deposits
B. Air entrainment during transfer
C. Ingress of water and dust through unprotected bungs
D. Additive precipitation due to cold
Correct Answer
Answer: C
Explanation: Outdoor horizontal storage with unprotected bungs can draw in water
and dust through thermal breathing cycles, especially at the top. KEW stresses
storing drums indoors, vertically, and bung closed/protected to prevent ingress.
Page 1 of 139
,Question 3
During regreasing, a technician pumps grease until it purges out the seals. What is the
main risk of this practice?
A. Lower film strength
B. Seal blowout or overpressurization, leading to grease churning and heat
C. Additive depletion
D. Bearing corrosion
Correct Answer
Answer: B
Explanation: Over-greasing increases pressure, may blow out seals, and leads to
churning, increasing temperature and reducing bearing life. Proper volume and
intervals are critical.
Question 4
Which oil-analysis method gives a quick, multi-parameter screen for oxidation by-
products (polar groups), water and other degradation markers and is commonly used
for trendable in-service checks?
A. Rotating Pressure Vessel Oxidation Test (RPVOT / ASTM D2272) only
B. FTIR (Fourier-Transform Infrared) spectroscopy
C. Particle counting (ISO 4406)
D. Copper corrosion (ASTM cup test)
Correct Answer
Answer: B.
Explanation: FTIR detects multiple degradation by-products (oxidation products,
nitration, water signatures) quickly and is widely used for screening and trending.
RPVOT measures oxidation stability (resistance) rather than directly quantifying in-
service oxidation products — both have roles, but FTIR is the broad, fast detect
method.
Page 2 of 139
,Question 5
A gear oil is analyzed. PQ index (Particle Quantifier) is high, but ferrous wear particle
count is low. Which interpretation fits best?
A. Ferrous wear particles are very fine and below sensor threshold
B. Particles are mainly non-ferrous metals
C. PQ sensor is malfunctioning
D. Sample was taken too late after shutdown
Correct Answer
Answer: A
Explanation: PQ index measures total ferrous mass magnetically, regardless of size.
Particle counters only measure particles above certain sizes. A high PQ + low count
indicates many small ferrous particles, often from incipient wear or fine grinding.
This is a common oil analysis interpretation scenario.
Question 6
Which of the following best describes the function of anti-wear (AW) additives like
ZDDP in boundary conditions?
A. Increasing oil viscosity at low temperature
B. Reacting with metal surfaces to form sacrificial films that prevent asperity welding
C. Neutralizing acidic oxidation products
D. Removing water by chemical reaction
Correct Answer
Answer: B
Explanation: AW additives (e.g., ZDDP) form sacrificial boundary films on metal
surfaces under pressure/temperature, preventing metal-to-metal contact and wear
in boundary lubrication regimes.
Page 3 of 139
, Question 7
Which of the following sampling methods is most likely to yield trending data that
underestimates actual contamination levels in a circulating system?
A. Sampling from a turbulent return line during operation
B. Sampling from an active manifold downstream of critical components
C. Sampling from the top of the reservoir after shutdown
D. Sampling from a live zone upstream of filters
Correct Answer
Answer: C
Explanation: Taking samples after shutdown and from stagnant reservoir zones
often leads to settled particles, giving false low readings. Best practice is turbulent
live-line sampling during operation.
Question 8
Two identical gearboxes are lubricated with different viscosity oils. Gearbox A has
higher operating temperature but lower wear. Gearbox B runs cooler, but wear metals
are higher. What is the most likely explanation?
A. Gearbox B oil is contaminated with water
B. Gearbox A has lower load
C. Gearbox B's oil is too low in viscosity, causing film failure despite cooler operation
D. Gearbox A has varnish buildup improving protection
Correct Answer
Answer: C
Explanation: Lower viscosity can reduce churning loss → lower temperature, but if
the viscosity is below optimum, it causes thinner films, increased asperity contact
and wear. stress picking viscosity for film formation, not just operating temp.
Page 4 of 139
Correct Answers / Latest Verified
Certification Exam Review with Rationales
Question 1
Which is a significant risk of mixing hydraulic oil with gear oil without compatibility
testing?
A. TAN increases immediately
B. Flash point doubles
C. Additives may precipitate, forming sludge and blocking filters
D. The oil separates into layers instantly
Correct Answer
Answer: C
Explanation: Additives from different formulations can react, causing precipitates,
sludge, and filter plugging. This is why compatibility testing and flushing are
essential before conversions.
Question 2
A technician wants to top-up a turbine reservoir with oil from a new drum. The
ambient temperature is 35 °C, and the drum has been stored outdoors, lying on its
side with bungs at 3 and 9 o'clock. What is the main contamination risk?
A. Varnish deposits
B. Air entrainment during transfer
C. Ingress of water and dust through unprotected bungs
D. Additive precipitation due to cold
Correct Answer
Answer: C
Explanation: Outdoor horizontal storage with unprotected bungs can draw in water
and dust through thermal breathing cycles, especially at the top. KEW stresses
storing drums indoors, vertically, and bung closed/protected to prevent ingress.
Page 1 of 139
,Question 3
During regreasing, a technician pumps grease until it purges out the seals. What is the
main risk of this practice?
A. Lower film strength
B. Seal blowout or overpressurization, leading to grease churning and heat
C. Additive depletion
D. Bearing corrosion
Correct Answer
Answer: B
Explanation: Over-greasing increases pressure, may blow out seals, and leads to
churning, increasing temperature and reducing bearing life. Proper volume and
intervals are critical.
Question 4
Which oil-analysis method gives a quick, multi-parameter screen for oxidation by-
products (polar groups), water and other degradation markers and is commonly used
for trendable in-service checks?
A. Rotating Pressure Vessel Oxidation Test (RPVOT / ASTM D2272) only
B. FTIR (Fourier-Transform Infrared) spectroscopy
C. Particle counting (ISO 4406)
D. Copper corrosion (ASTM cup test)
Correct Answer
Answer: B.
Explanation: FTIR detects multiple degradation by-products (oxidation products,
nitration, water signatures) quickly and is widely used for screening and trending.
RPVOT measures oxidation stability (resistance) rather than directly quantifying in-
service oxidation products — both have roles, but FTIR is the broad, fast detect
method.
Page 2 of 139
,Question 5
A gear oil is analyzed. PQ index (Particle Quantifier) is high, but ferrous wear particle
count is low. Which interpretation fits best?
A. Ferrous wear particles are very fine and below sensor threshold
B. Particles are mainly non-ferrous metals
C. PQ sensor is malfunctioning
D. Sample was taken too late after shutdown
Correct Answer
Answer: A
Explanation: PQ index measures total ferrous mass magnetically, regardless of size.
Particle counters only measure particles above certain sizes. A high PQ + low count
indicates many small ferrous particles, often from incipient wear or fine grinding.
This is a common oil analysis interpretation scenario.
Question 6
Which of the following best describes the function of anti-wear (AW) additives like
ZDDP in boundary conditions?
A. Increasing oil viscosity at low temperature
B. Reacting with metal surfaces to form sacrificial films that prevent asperity welding
C. Neutralizing acidic oxidation products
D. Removing water by chemical reaction
Correct Answer
Answer: B
Explanation: AW additives (e.g., ZDDP) form sacrificial boundary films on metal
surfaces under pressure/temperature, preventing metal-to-metal contact and wear
in boundary lubrication regimes.
Page 3 of 139
, Question 7
Which of the following sampling methods is most likely to yield trending data that
underestimates actual contamination levels in a circulating system?
A. Sampling from a turbulent return line during operation
B. Sampling from an active manifold downstream of critical components
C. Sampling from the top of the reservoir after shutdown
D. Sampling from a live zone upstream of filters
Correct Answer
Answer: C
Explanation: Taking samples after shutdown and from stagnant reservoir zones
often leads to settled particles, giving false low readings. Best practice is turbulent
live-line sampling during operation.
Question 8
Two identical gearboxes are lubricated with different viscosity oils. Gearbox A has
higher operating temperature but lower wear. Gearbox B runs cooler, but wear metals
are higher. What is the most likely explanation?
A. Gearbox B oil is contaminated with water
B. Gearbox A has lower load
C. Gearbox B's oil is too low in viscosity, causing film failure despite cooler operation
D. Gearbox A has varnish buildup improving protection
Correct Answer
Answer: C
Explanation: Lower viscosity can reduce churning loss → lower temperature, but if
the viscosity is below optimum, it causes thinner films, increased asperity contact
and wear. stress picking viscosity for film formation, not just operating temp.
Page 4 of 139
