Related Clues:

• Alley sounds
• Good engine sounds
• Catty comments
• Sounds of contentment
• Doesn't knock or ping
• Catty remarks
• Runs smoothly, as an engine
• Engine sounds
• Runs smoothly
• Contented sounds
• Kitty cries
• Satisfied sounds
• Siamese language?
• Hums like an engine
• Cat calls