Which among the following is not the main function of lubricating oil?

Correct option is A

There are 6 Basic Functions of a Lubricant/Oil.
1. Lubrication – Provide a film between moving parts.
2. Cooling – Heat transfer media.
3. Sealing – Filling in uneven surfaces
4. Cleaning – Holding contaminants in suspension.
5. Dampening & Cushioning – Of components under high stress.
6. Protection – From oxidation & corrosion.
Examine each option:
(a) To maintain the temperature of the engine: Not a primary function. Lubricating oil helps in cooling by transferring heat but does not control or regulate the engine temperature.
(b) To reduce the friction: Lubricating oil forms a film between moving parts, reducing friction and preventing wear.
(c) To reduce wear and tear: The oil reduces wear by minimizing metal-to-metal contact and protecting surfaces from damage.
(d) To take away the heat from the piston: The oil helps in cooling engine components by absorbing and transferring heat away from hot areas like the piston.
(e) To act as a seal between the piston and cylinder: Lubricating oil helps to create a seal, reducing blow-by and maintaining compression.