Engine needing check in US state (7)
I believe the answer is:
machine
'engine' is the definition.
(thesaurus)
'check in us state' is the wordplay.
'check' becomes 'ch' (I've seen this in other clues).
'in' is an insertion indicator.
'us state' becomes 'maine' (I've seen this before).
'ch' inserted into 'maine' is 'MACHINE'.
'needing' acts as a link.
(Other definitions for machine that I've seen before include "Device providing energy to perform a task" , "Mechanical contrivance; engine" , "Powered mechanism" , "See 12" , "Well-organised and powerful group" .)