Question

A rise in cooling water temperature ____________ engine friction through its effect on oil viscosity.

(a) increases

(b) reduces

(c) unpredictable

(d) none of the mentioned

This question was posed to me in my homework.

My doubt is from Engine Friction topic in chapter Engine Friction and Lubrication of IC Engine

Answer 1

The correct answer is:

(a) increases

A rise in cooling water temperature typically increases engine friction through its effect on oil viscosity. As the temperature of the engine increases, the viscosity of the oil decreases, leading to less effective lubrication and higher friction between engine components.