Sound of hooter I installed (5)
I believe the answer is:
noise
'sound' is the definition.
(noise is a kind of sound)
'hooter i installed' is the wordplay.
'hooter' becomes 'nose' (I've seen this before).
'installed' is an insertion indicator.
'nose' enclosing 'i' is 'NOISE'.
'of' is the link.
(Other definitions for noise that I've seen before include "Unwanted sound" , "Racket, din" , "Din, cacophony" , "explosive report, for example" , "Row" .)