| Answer | Crossword Clue |
|---|---|
| PURR | Smooth-running engine sound |
| HUM | Smooth engine sound |
| PURR | Smooth engine sound |
| PURR | Smooth-running sound |
| PURRS | Smooth engine sounds |
| lubricated | Apply a substance such as oil or grease to (an engine or component) to minimize friction and allow smooth movement |
| lubricates | Apply a substance such as oil or grease to (an engine or component) to minimize friction and allow smooth movement |
| lubricating | Apply a substance such as oil or grease to (an engine or component) to minimize friction and allow smooth movement |
