What can cause the engine to lock?
- Shifting gears improperly
- Braking with only one brake
- The front tire skidding
- Being low on oil ✓
Answer: D. Being low on oil
Being low on oil can cause the engine to lock, because a lack of lubrication leads to engine seizure.
Why this is the answer
The handbook explains that engine seizure means the engine locks or freezes, and it lists overheating or a lack of lubrication as the cause. Without oil, the moving parts inside the engine no longer slide smoothly against each other and the engine overheats. The passage adds that you may get warning first, such as a loss of engine power or a change in the engine's sound, and that you should pull off the road and let it cool. Running low on oil is therefore the situation that leads to a locked engine.
Why the other answers are wrong
- A. Shifting gears improperly — The passages say nothing about shifting gears badly causing the engine to lock; the stated causes are overheating and a lack of lubrication.
- B. Braking with only one brake — Braking with only one brake is not mentioned in the passages as a cause of engine seizure.
- C. The front tire skidding — A skidding front tire is not described as a cause of a locked engine; the passage on seizure ties locking to oil and heat.
Remember it
Think of the engine as needing oil to slide freely: no oil, no smooth movement, and it locks up.