hi everybody, got home earlier after a short journey from work (5 miles) and on putting my 172 in the garage i could hear a loud ticking/rattling noise. on investigation the noise does go after i rev the car up but once back to idle the noise returns. sounds near top right (cambelt end) of engine. i have read that the dephaser pully is a common fault. what i need to know is can i still drive the car? how much to fix? will i need everything else replaced, ie cambelt, tensioner, aux belt etc? thanks if anybody can help.