When I start my Renault Megane in the morning there is a loud noise this only happens once a day. Is it serious

Jac, March 2012

sounds like the cam belt diffuser starts off as a low rattle , after a few days gets louder , then you have to try twice to get it started . This is a known problem on Renault but they wouldnt fix it until they had heard it and as you said it usually only happens when the car has not been used, took them three attempts to fix mine though luckily it was under warrenty at the time

mike, March 2012

you might have a problem with your starter/ring gear and not sure on your model whether it has a dual mass flywheel and without hearing the fault it is very difficult to say,another thing to try would be to remove the fanbelt and see if the noise disappears when cranking over,try and get someone to listen into the engine bay each morning to try and determine what sort of area the noise is coming from and post back on here with your fingings good luck

cdc, March 2012

its when I push button to start as the engine turns over it has a loud rattle, dosn't actually start, then I try it again and it's fine. It dosen't happen the rest of the day , and not every day.

jac, March 2012

you will have to be more specific,is it when you are cranking over the engine? has it started and ticking over?does it go away with your foot on the clutch?are you on the move when you hear it?is it a squeal/knocking/rumbling?how long does it last for?is it a petrol/diesel?the problem on this site is the majority of people don`t give enough information and a lot of questions are nigh on impossible to determine the fault,especially on modern veh`s

cdc, March 2012