3 year old MX5, New Shape, 1.8, 5 Speed Box.
Clutch out when idling, noise like a marble being rolled around in a biscuit tin.
Clutch in, silence.
Input shaft bearing?, or, as seems to be said on the Internet - normal?
Worse when hot … almost silent when cold.
Covered under extended warranty?
Hmm I get this but not as bad as you seem to be implying - I was going to bring up ‘transmission chatter when idling’ when I take it in for its service tomorrow (last one before standard warranty runs out so have a list of things for them to check lol), so I will report back to you. In mine I only hear it when in garage with roof down - idling in neutral there is a vague sound as you describe, but quiet. As you say it vanishes when clutch pushed in. I haven’t noticed mine change with temp, but that is more likely to be because I hardly ever put it straight back in garage after run. As I say, I will get you some feedback after I speak to dealer about it tomorrow. If anyone else has any opinion/experience that will be interesting for me to know too.
http://mx5oc.co.uk/forum/forums/t/314.aspx
Stuff from the FAQ-----
Hmm that’s not the same chatter I have - mine is only in neutral when stationary, and disappears when clutch is pressed or gear is engaged. I never notice anything when driving.
Sounds like a gear roll-over noise to me. Nothing to worry about.
Yeah not particularly worried - just want them to check EVERYTHING before warranty expires so being over-picky! lol
Hmm! Why not clutch release bearing ?, This would be the first thing that comes to mind if someone said to me noise with clutch up and no noise with it depressed.
Would that have any other symptoms?
Because clutch release bearing noise is rare especially on an NC. Gear roll-over noise is common.
Often no other symptons , except a rumbling or squeaking that disapears when the clutch is depressed. However eventually, failure will cause the clutch not to operate correctly or not at all.
However it must be worth listening to those with in depth experience specifically related to the 5 as I am just talking in general motioring terms.
Dealer said nothing to worry about or unusual - mind you, I expected that lol