Level 1 MLT & MLA Practice Exam
LEVEL 1 MLT & MLA PRACTICE EXAM PREPARATION NEWEST
2025/2026 WITH COMPLETE QUESTIONS AND CORRECT
DETAILED ANSWERS| BRAND NEW VERSION!
Which is not a type of base oil (base stock)?
a) Mineral
b) Synthetic
c) Antioxidant
d) Vegetable
e) Group III synthetic
Answer: "c"
All of these options are base oil types except antioxidant, which is an additive
that is added to the base oil to improve oxidation stability.
Benefits generally associated with the use of synthetics include:
a) Better oxidation resistance
b) Better compatibility with clastomers (seals)
c) Less toxicity
d) Higher cost
e) Better paint compatibility
Answer: "a"
In general, synthetic base oils have better oxidation stability. However, most
synthetics are incompatible with clastomers (seals), as they cause the scals to
swell or shrink. Some synthetics can also be toxic. High cost and incompatibility
with paints are other shortcomings of synthetics, so the correct answer is (a).
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, Level 1 MLT & MLA Practice Exam
PAO synthetic base oils:
a) Offer the best additive solubility
b) Are the prime choice for fire resistance
c) Have better oxidation stability than mineral oils
d) Are incompatible with mineral oils
e) Offer the very best high-temperature stability
Answer: "c"
PAO base oils have high oxidation stability compared to mineral oils. The
additive solubility is limited because of the high degree of purity (the more
refined the base oil, the less solubility of the additives). Furthermore, PAO base
oils are compatible with mineral oils but are not fire-resistant fluids, so the
correct answer is (c).
Polyglycol (PAG) synthetic oils:
a) Offer the best additive solubility
b) Are the prime choice for fire-resistant fluids
c) Are a copy of the best structure found in mineral oils
d) Are incompatible with mineral oils
e) Offer the very best high-temperature stability
Answer: "d"
PAG oil offers marginal additive solubility. While it is fire resistant when
combined with water (water-glycol), it is not the prime choice for fire-resistant
fluids. (Phosphate ester is the prime fire-resistant choice.) PAG has a totally
different structure than mineral oil. It offers high-temperature stability, but it is
not the best high temperature option. For instance, ester-based fluids have
higher temperature stability than PAG. PAG oils also are incompatible with
mineral oil, so the correct answer is (d).
2|Page
, Level 1 MLT & MLA Practice Exam
Greases have the advantage of functioning well in:
a) Very high-speed bearings
b) Frequent start-stop applications
c) The presence of other types of greases
d) Applications that require heat transfer and cooling
e) Very cold-temperature applications
Answer: "b"
Grease remains within the lubricated component, lowering the risk of a dry
start. It is unlike oil, which drains away when the system is shut down.
What is the prime advantage to newer "complex" soap thickeners vs. older simple
soap thickeners?
a) Higher cost
b) More appealing color
c) Harder grease
d) Higher dropping point and thus higher operating temperature
e) Better low-temperature pumping
Answer: "d"
Both simple and complex soaps comprise long-chain fatty acids and metal
hydroxide. The main difference between simple and complex soaps is the
presence of short-chain fatty acids in complex soaps. This improves the thermal
stability of the thickener and leads to higher dropping points and thus higher
operating temperatures. The dropping point of a grease is the temperature at
which it passes from a semi-solid to a liquid state under specific test conditions
Compatibility of different greases:
a) is only a minor issue and often can be ignored
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, Level 1 MLT & MLA Practice Exam
b) Is a major issue that is dependent on the thickener used
c) Is independent of the thickeners used d) Can be linked to the age of the grease
involved
e) is dependent only on the base oil used
Answer: "b"
Compatibility of different greases is a serious issue that mainly depends on the
thickener type. In general, most grease thickeners are incompatible, so extreme
caution is required when switching from one grease type to another.
Which is the most common type of grease thickener?
a) Lithium
b) Barium
c) Polyurea
d) Calcium
c) Aluminum
Answer: "a"
All of these are grease thickeners, but the most common type is lithium.
Which one of the following is an NLGI grade?
a) 00
b) 30
c) 90
d) 220
e) 460
Answer: "a"
NLGI numbers represent grease consistency. The higher the number, the stiffer
4|Page
LEVEL 1 MLT & MLA PRACTICE EXAM PREPARATION NEWEST
2025/2026 WITH COMPLETE QUESTIONS AND CORRECT
DETAILED ANSWERS| BRAND NEW VERSION!
Which is not a type of base oil (base stock)?
a) Mineral
b) Synthetic
c) Antioxidant
d) Vegetable
e) Group III synthetic
Answer: "c"
All of these options are base oil types except antioxidant, which is an additive
that is added to the base oil to improve oxidation stability.
Benefits generally associated with the use of synthetics include:
a) Better oxidation resistance
b) Better compatibility with clastomers (seals)
c) Less toxicity
d) Higher cost
e) Better paint compatibility
Answer: "a"
In general, synthetic base oils have better oxidation stability. However, most
synthetics are incompatible with clastomers (seals), as they cause the scals to
swell or shrink. Some synthetics can also be toxic. High cost and incompatibility
with paints are other shortcomings of synthetics, so the correct answer is (a).
1|Page
, Level 1 MLT & MLA Practice Exam
PAO synthetic base oils:
a) Offer the best additive solubility
b) Are the prime choice for fire resistance
c) Have better oxidation stability than mineral oils
d) Are incompatible with mineral oils
e) Offer the very best high-temperature stability
Answer: "c"
PAO base oils have high oxidation stability compared to mineral oils. The
additive solubility is limited because of the high degree of purity (the more
refined the base oil, the less solubility of the additives). Furthermore, PAO base
oils are compatible with mineral oils but are not fire-resistant fluids, so the
correct answer is (c).
Polyglycol (PAG) synthetic oils:
a) Offer the best additive solubility
b) Are the prime choice for fire-resistant fluids
c) Are a copy of the best structure found in mineral oils
d) Are incompatible with mineral oils
e) Offer the very best high-temperature stability
Answer: "d"
PAG oil offers marginal additive solubility. While it is fire resistant when
combined with water (water-glycol), it is not the prime choice for fire-resistant
fluids. (Phosphate ester is the prime fire-resistant choice.) PAG has a totally
different structure than mineral oil. It offers high-temperature stability, but it is
not the best high temperature option. For instance, ester-based fluids have
higher temperature stability than PAG. PAG oils also are incompatible with
mineral oil, so the correct answer is (d).
2|Page
, Level 1 MLT & MLA Practice Exam
Greases have the advantage of functioning well in:
a) Very high-speed bearings
b) Frequent start-stop applications
c) The presence of other types of greases
d) Applications that require heat transfer and cooling
e) Very cold-temperature applications
Answer: "b"
Grease remains within the lubricated component, lowering the risk of a dry
start. It is unlike oil, which drains away when the system is shut down.
What is the prime advantage to newer "complex" soap thickeners vs. older simple
soap thickeners?
a) Higher cost
b) More appealing color
c) Harder grease
d) Higher dropping point and thus higher operating temperature
e) Better low-temperature pumping
Answer: "d"
Both simple and complex soaps comprise long-chain fatty acids and metal
hydroxide. The main difference between simple and complex soaps is the
presence of short-chain fatty acids in complex soaps. This improves the thermal
stability of the thickener and leads to higher dropping points and thus higher
operating temperatures. The dropping point of a grease is the temperature at
which it passes from a semi-solid to a liquid state under specific test conditions
Compatibility of different greases:
a) is only a minor issue and often can be ignored
3|Page
, Level 1 MLT & MLA Practice Exam
b) Is a major issue that is dependent on the thickener used
c) Is independent of the thickeners used d) Can be linked to the age of the grease
involved
e) is dependent only on the base oil used
Answer: "b"
Compatibility of different greases is a serious issue that mainly depends on the
thickener type. In general, most grease thickeners are incompatible, so extreme
caution is required when switching from one grease type to another.
Which is the most common type of grease thickener?
a) Lithium
b) Barium
c) Polyurea
d) Calcium
c) Aluminum
Answer: "a"
All of these are grease thickeners, but the most common type is lithium.
Which one of the following is an NLGI grade?
a) 00
b) 30
c) 90
d) 220
e) 460
Answer: "a"
NLGI numbers represent grease consistency. The higher the number, the stiffer
4|Page
