One making checks about new outlet (4)
I believe the answer is:
vent
'outlet' is the definition.
(I know that outlet can be written as vent)
'one making checks about new' is the wordplay.
'one making checks' becomes 'vet' (a vet checks an animal's health).
'about' is an insertion indicator.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'vet' going around 'n' is 'VENT'.
(Other definitions for vent that I've seen before include "Give outlet as to feelings" , "Hole allowing gas or air to escape" , "Opening releasing gas" , "Orifice" , "Opening for air" .)