Hi, when my z has been sat over night and u start it up there is a whine come from the engine, it only lasts a minute or so and I think it is worse when the clutch is pressed, not 100% but sure it's louder, the problem is it gets quieter and quieter the longer the engine runs giving me little time to diagnose, also, the whine changes frequency in relation to engine speed. It sounds like it may be a belt whining, how can I diagnose or what else should I be checking?

 

Thanks, Dan

might be the clutch bearing...

 

aside from that check the tension of all the belts and check for wear as well.

it's hard to tell without hearing what kind of whine.

 

slipping all the aux belts off will eliminate them from the equation, but the fact that it gets worse with the clutch in would be harder. As said it might be the release/thrust bearing but normally that doesnt fade after a few mins and is always there as a grumble.