Noise just started from under bonnet?

[t3stin]

I have noticed since yesterday when I start the car it sounds a bit tappy but once warm
there is a hard to describe sound...sort of the whirring noise of a helicopter (when idle) or a belt noise -
to me it sounds like it is coming from one of the belts and It is almost due a timing belt change - could it be this? Is it something i need to worry about?

I appreciate its hard to second guess what a noise is but i'd love your thoughts...thanks!

[t3stin]

should probably also point out that it isnt really loud or anything but it is noticable..

[davelowe]

Depends to a degree on what engine you have. Flapping belts indicate that either the belt itself is worn, or whatever it drives is suspiciously defective. If, the belt(s) is/are to blame.

Bearings in the tensioner, water pump, alternator etc can cause noises. If you remove the belts as part of their replacement, you can spin the components and listen to any adverse sounds.

I would have the belts changed asap. If the timing belt snaps, it is the end of the life of the engine to all intents and purposes.

[morganjake1544]

Could be one of the belts fraying on the edge (which sounds like you've stuck a plastic lolly stick in your bicycle spokes). Needs seeing to as if it's a big piece flaying the engine bay it can do some expensive damage. Look to see if you can see any loose stringy bits, and trim off.
Agree with Dave, bring forward belt replacement.

[t3stin]

appreciate the replies guys - In case anyone elses has a similar issue i got it to the garage yesterday to get the timing belt and water pump replaced and was told the noise was actually the water pump on its way out.

Pleased to say the noise has gone and car feels better in general.

[davelowe]

Result! You may just have saved your engine!