Fintan Treanor, 20, was walking home in the early hours of Sunday, 26 June 2011, when he was struck by a vehicle at Lemgare, Clontibret.
He had been walking home after a night out in Castleblaney.
Police appeals have centred on an Audi A4 1995 to 2001 model missing its front lower air-vent grille.
"Five years have passed and the driver of the car involved has not been located," a gardai (Irish police) spokesperson said.
"Perhaps now after five years some person knows a person who disposed of an Audi A4 around that time.
"In five years, loyalties, friendships and relationships change and perhaps someone that felt unable to come forward before is now in a position to provide the investigation team with the vital information that would locate the driver."
Police have renewed their appeal for information on the fifth anniversary of a fatal hit-and-run collision in County Monaghan.