The phrase "ticking sound" refers to a repetitive noise similar to the sound of a clock ticking.
Sentences with «ticking sound»
Over time I have heard a very very faint ticking sound which never really concerned me car ran perfect otherwise and the sound was so faint. (mechanics.stackexchange.com)
KEY PRODUCT POINTS Clock does not make ticking sound. (potterybarn.com)
When the exhaust gasket begins to fail, this may cause this type of ticking sound as the engine RPM's increase. (yourmechanic.com)