Is it advisable to use a lubricating oil with such a low viscosity index that, when the engine heats up, it becomes excessively fluid?
A)Yes; the more fluid, the better it lubricates and it also carries away deposits in the engine.
B)Only if the engine overheats, since it lubricates better and helps lower its temperature.
C)No, because the oil does not properly lubricate the engine parts.Correct
# Explanation
It is not advisable to use an oil with a very low viscosity index. When the engine heats up, an oil that is too fluid loses its ability to form a protective film between the moving parts, which leads to poor lubrication and greater engine wear. The oil must maintain adequate viscosity at all operating temperatures to ensure effective lubrication.