Final answer:
Using WD-40 as engine oil results in lubrication failure and potentially engine overheating due to its unsuitability for high-pressure, high-temperature environments of an automobile engine, especially during extended periods of high RPMs in neutral.
Step-by-step explanation:
The correct option : d
Engine oil is designed to lubricate, clean, and cool the internal components of an engine. WD-40, while a lubricant, is not formulated for the high-pressure, high-temperature environments found inside an engine. WD-40 has a relatively low flash point and viscosity compared to proper engine oil, which can lead to inadequate lubrication, rapid breakdown, and eventually, overheating and damage to engine components. When the vehicle is in neutral, and acceleration is applied, the engine operates at high RPMs without the cooling effect of air flow that it would normally get while the vehicle is in motion.
This can result in the engine components heating up more quickly than usual. If WD-40 is used in place of engine oil, it would be even less capable of dissipating this heat, leading to an even quicker breakdown of the lubricant and potential engine overheating. Also, the lubrication properties required to protect moving parts within the engine cannot be sustained by WD-40, and therefore, with its use, engine lubrication fails. This can cause metal-on-metal contact, leading to increased wear, friction, and eventually, catastrophic engine failure.