Practice Test Geeks(CLS) Certified Lubrication Specialist Practice Test
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Lubricant Selection & Management Flashcards

7 cards from real CLS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

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  1. A worm gear drive requires a lubricant to handle sliding contact between steel and bronze components. Which additive type should be avoided?

    Answer: Sulfur-based EP additives

    Sulfur-based EP additives corrode bronze and other yellow metals, making them unsuitable for worm gear drives with bronze components.

  2. The Viscosity Index (VI) of a lubricant measures its:

    Answer: Rate of viscosity change with temperature

    Viscosity Index quantifies how much a lubricant's viscosity changes with temperature; a higher VI means less viscosity change.

  3. Which synthetic base oil type offers the best performance for very wide operating temperature ranges, from -60°F to +400°F?

    Answer: Silicone fluid

    Silicone fluids maintain usable viscosity across extremely wide temperature ranges, from very low to very high temperatures, surpassing PAOs.

  4. A technician notices a gear oil has turned milky white in color. This most likely indicates:

    Answer: Water contamination

    A milky or cloudy white appearance in gear oil is a classic sign of water emulsification or contamination.

  5. When lubricating an open gear drive exposed to washout and contamination, which lubricant form is most appropriate?

    Answer: Asphaltic (bituminous) open gear compound

    Asphaltic open gear compounds provide extreme adhesiveness and high film thickness to cling to teeth and resist wash-off under harsh exposure.

  6. Which AGMA lubricant number corresponds approximately to an ISO VG 460 industrial gear oil?

    Answer: AGMA 8

    AGMA 8 corresponds to an approximate ISO VG 460 viscosity range for industrial gear lubricants.

  7. A plant has multiple hydraulic systems requiring different viscosity oils. What is the primary risk of using a higher-than-specified viscosity hydraulic oil?

    Answer: Increased pump cavitation and reduced efficiency

    Oil that is too viscous increases resistance to flow, which can cause pump cavitation, reduced efficiency, and poor response in cold start conditions.