Technician A says that viscosity index (VI) improvers thicken oil when it becomes hot and thins it when it becomes cold. Technician B says that VI improvers thin oil when it's hot and thicken it when it's cold. Who is correct?
A)Technician A
B)Technician B
C)Both A and B
D)Neither A nor B

Question

Quizplus · Accepted Answer

Viscosity index (VI) improvers are additives that help to maintain the viscosity of oil over a wide temperature range. When the oil is hot, the VI improvers thicken the oil to prevent it from becoming too thin. When the oil is cold, the VI improvers thin the oil to prevent it from becoming too thick.

Technician a Says That Viscosity Index (VI) Improvers Thicken Oil