Male radio geek's broadcast runs flawlessly (4,4,1,5)
I believe the answer is:
goes like a dream
'runs flawlessly' is the definition.
'male radio geek's broadcast' is the wordplay.
'broadcast' indicates an anagram.
'male'+'radio'+'geeks'='maleradiogeeks'
'maleradiogeeks' with letters rearranged gives 'GOES LIKE A DREAM'.
(Other definitions for goes like a dream that I've seen before include "disappears as if an illusion had been shattered?" , "Works very well" .)