Machinery Lubrication Technician
Certification (MLA Level 2) Practice
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. Which of the following is the primary function of lubricants in
machinery?
A) Cooling
B) Reducing friction
C) Cleaning
D) Sealing
Rationale:
Lubricants primarily reduce friction between moving parts, minimizing
wear and energy loss.
, 2. What is the typical viscosity range for a hydraulic oil used in mobile
equipment?
A) 5–10 cSt
B) 10–20 cSt
C) 15–46 cSt
D) 50–100 cSt
Rationale:
Hydraulic oils are selected for appropriate viscosity to ensure proper flow
and protection in mobile equipment, typically between 15–46 cSt.
3. Which additive is commonly used in lubricants to prevent corrosion?
A) Detergents
B) Rust inhibitors
C) Anti-foam agents
D) Viscosity index improvers
Rationale:
Rust inhibitors are added to oils to protect metal surfaces from oxidation
and corrosion.
4. Which lubricant property measures resistance to flow at high
temperature?
A) Flash point
B) Pour point
C) Viscosity index
D) Oxidation stability
,Rationale:
Viscosity index indicates how much a lubricant’s viscosity changes with
temperature, providing stability under varying operating conditions.
5. What is the main purpose of an oil analysis program?
A) Determine lubricant color
B) Detect wear and contamination early
C) Increase lubricant viscosity
D) Reduce lubricant cost
Rationale:
Oil analysis helps detect abnormal wear, contamination, and lubricant
degradation before failure occurs.
6. Which of the following is a sign of bearing fatigue?
A) Low oil temperature
B) Spalling on the raceway
C) High lubricant viscosity
D) Reduced flow rate
Rationale:
Spalling or flaking on bearing surfaces indicates fatigue failure, often due
to insufficient lubrication or overloading.
7. The ASTM D4172 test evaluates which property of lubricants?
A) Oxidation stability
B) Corrosion protection
, C) Anti-wear performance
D) Pour point
Rationale:
The D4172 test measures the wear protection performance of a lubricant
under controlled conditions.
8. Which type of lubricant is recommended for high-speed electric
motors?
A) Grease with high NLGI grade
B) Low-viscosity mineral oil
C) Heavy gear oil
D) Molybdenum disulfide grease
Rationale:
Low-viscosity mineral oils reduce heat buildup and provide proper film
thickness for high-speed electric motors.
9. Water contamination in oil primarily causes:
A) Improved lubrication
B) Corrosion and reduced film strength
C) Increased viscosity
D) Higher oxidation stability
Rationale:
Water promotes corrosion, reduces oil film strength, and accelerates
additive degradation.
Certification (MLA Level 2) Practice
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. Which of the following is the primary function of lubricants in
machinery?
A) Cooling
B) Reducing friction
C) Cleaning
D) Sealing
Rationale:
Lubricants primarily reduce friction between moving parts, minimizing
wear and energy loss.
, 2. What is the typical viscosity range for a hydraulic oil used in mobile
equipment?
A) 5–10 cSt
B) 10–20 cSt
C) 15–46 cSt
D) 50–100 cSt
Rationale:
Hydraulic oils are selected for appropriate viscosity to ensure proper flow
and protection in mobile equipment, typically between 15–46 cSt.
3. Which additive is commonly used in lubricants to prevent corrosion?
A) Detergents
B) Rust inhibitors
C) Anti-foam agents
D) Viscosity index improvers
Rationale:
Rust inhibitors are added to oils to protect metal surfaces from oxidation
and corrosion.
4. Which lubricant property measures resistance to flow at high
temperature?
A) Flash point
B) Pour point
C) Viscosity index
D) Oxidation stability
,Rationale:
Viscosity index indicates how much a lubricant’s viscosity changes with
temperature, providing stability under varying operating conditions.
5. What is the main purpose of an oil analysis program?
A) Determine lubricant color
B) Detect wear and contamination early
C) Increase lubricant viscosity
D) Reduce lubricant cost
Rationale:
Oil analysis helps detect abnormal wear, contamination, and lubricant
degradation before failure occurs.
6. Which of the following is a sign of bearing fatigue?
A) Low oil temperature
B) Spalling on the raceway
C) High lubricant viscosity
D) Reduced flow rate
Rationale:
Spalling or flaking on bearing surfaces indicates fatigue failure, often due
to insufficient lubrication or overloading.
7. The ASTM D4172 test evaluates which property of lubricants?
A) Oxidation stability
B) Corrosion protection
, C) Anti-wear performance
D) Pour point
Rationale:
The D4172 test measures the wear protection performance of a lubricant
under controlled conditions.
8. Which type of lubricant is recommended for high-speed electric
motors?
A) Grease with high NLGI grade
B) Low-viscosity mineral oil
C) Heavy gear oil
D) Molybdenum disulfide grease
Rationale:
Low-viscosity mineral oils reduce heat buildup and provide proper film
thickness for high-speed electric motors.
9. Water contamination in oil primarily causes:
A) Improved lubrication
B) Corrosion and reduced film strength
C) Increased viscosity
D) Higher oxidation stability
Rationale:
Water promotes corrosion, reduces oil film strength, and accelerates
additive degradation.
