CLS CLS Oil Analysis & Condition Monitoring

Question 1

Which oil analysis test is primarily used to detect the presence of water contamination in a lubricant?

Accepted Answer

Crackle test

Answer

The crackle test involves placing a drop of oil on a hot plate; water contamination causes crackling or bubbling.

Question 2

What does a rising ferrous density (FD) value in an oil analysis report most likely indicate?

Accepted Answer

Increased wear of ferrous metal components

Answer

Rising ferrous density indicates increasing iron particle concentration, signaling accelerated wear of steel or cast iron parts.

Question 3

The viscosity of an in-service lubricant has increased by 25% from its new-oil baseline. What is the most probable cause?

Accepted Answer

Oxidation and thermal degradation

Answer

Oxidation and thermal degradation form varnish and sludge precursors that significantly thicken the oil.

Question 4

Which elemental spectroscopy technique is most commonly used in oil analysis to identify wear metals?

Accepted Answer

Inductively Coupled Plasma (ICP)

Answer

ICP spectroscopy accurately measures concentrations of wear metals, contaminants, and additive elements in parts per million.

Question 5

A Total Base Number (TBN) test on a diesel engine oil shows a value that has dropped to less than 50% of the new-oil TBN. What does this indicate?

Accepted Answer

The oil's acid-neutralizing capacity is significantly depleted

Answer

TBN measures the oil's ability to neutralize combustion acids; a drop below 50% signals the need for an oil change.

(CLS) Certified Lubrication Specialist Practice Test