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Free ICML MLT I Practice Questions

10 free, exam-style Machinery Lubrication Technician I (ICML MLT I) practice questions with answers and explanations. No signup required. Work through them below, then take the full free ICML MLT I practice test to study every exam domain.

These 10 free ICML MLT I questions are organized by exam domain, so you can see how each part of the Machinery Lubrication Technician I blueprint is tested. Reveal the answer and explanation under each question.

Domain 2: Lubrication Theory 10% of exam

Question 1

A heavily loaded machine is just beginning to turn at startup, before it reaches operating speed. Which lubrication regime is the surfaces MOST likely operating in at this moment?

  1. Hydrodynamic
  2. Boundary
  3. Elastohydrodynamic
  4. Mixed-film
Show answer & explanation

Correct answer: B - Boundary

Domain 3: Lubricants 15% of exam

Question 2

Which NLGI consistency grade is the general-purpose default used for most rolling-element bearings operating at moderate speed and temperature?

  1. NLGI 0
  2. NLGI 1
  3. NLGI 2
  4. NLGI 4
Show answer & explanation

Correct answer: C - NLGI 2

Question 3

A polyalphaolefin (PAO) synthetic base oil belongs to which API base oil group?

  1. Group II
  2. Group III
  3. Group V
  4. Group IV
Show answer & explanation

Correct answer: D - Group IV

Question 4

A technician tops off a bearing already packed with a lithium-soap grease using a polyurea grease. What is the MOST likely consequence of this incompatible mix?

  1. The mixed grease softens and may bleed oil from the bearing
  2. The dropping point rises and the grease tolerates more heat
  3. Load capacity improves
  4. No measurable effect
Show answer & explanation

Correct answer: A - The mixed grease softens and may bleed oil from the bearing

Domain 4: Lubricant Selection 15% of exam

Question 5

A gearbox nameplate specifies AGMA 5 gear oil. Which ISO viscosity grade is the closest equivalent?

  1. ISO VG 150
  2. ISO VG 220
  3. ISO VG 68
  4. ISO VG 460
Show answer & explanation

Correct answer: B - ISO VG 220

Domain 5: Lubricant Application 25% of exam

Question 6

A grease-lubricated bearing has an outer diameter (D) of 4 in and a width (B) of 1 in. Using the industry rule of thumb G (oz) = 0.114 × D × B, the amount of grease required for relubrication is approximately:

  1. 0.46 oz
  2. 1.14 oz
  3. 0.11 oz
  4. 4.56 oz
Show answer & explanation

Correct answer: A - 0.46 oz

Question 7

Compared with an identical bearing mounted on a horizontal shaft, a bearing mounted on a VERTICAL shaft should generally be regreased:

  1. At the same interval as a horizontal bearing
  2. More frequently
  3. Less frequently
  4. Only on failure
Show answer & explanation

Correct answer: B - More frequently

Question 8

What is the PRIMARY risk of over-greasing an electric motor bearing?

  1. Bearing seal damage and overheating from churning
  2. Stronger boundary film and better corrosion protection over time
  3. A lower steady-state operating temperature
  4. Reduced grease consumption
Show answer & explanation

Correct answer: A - Bearing seal damage and overheating from churning

Domain 7: Lube Condition Control 10% of exam

Question 9

In a modern ISO 4406 cleanliness code such as 18/16/13, the three numbers represent the counts of particles per millilitre larger than which sizes?

  1. 2, 5 and 15 micrometres
  2. 5, 10 and 25 micrometres
  3. 4, 6 and 14 micrometres
  4. 1, 2 and 5 micrometres
Show answer & explanation

Correct answer: C - 4, 6 and 14 micrometres

Question 10

A filter is rated with a beta ratio of β6 = 200. Using efficiency = (1 − 1/β) × 100, what is its approximate capture efficiency for particles 6 micrometres and larger?

  1. 50%
  2. 90%
  3. 99.5%
  4. 99.95%
Show answer & explanation

Correct answer: C - 99.5%

The rest of the ICML MLT I blueprint

The ICML MLT I exam also covers these domains. Drill them in the full free practice test:

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