Hello everyone.
I currently own a Fiat Punto 1.2 8v ELX.
Im not a mechanic so I barely know anything so anyone that could give me some advice I would appreciate it if you treated me/ talked me through things like you were talking to a child

After driving around for a period of time the engine (Or so I assume) starts to whine. It happens whether im in gear or in neutral. It tends to get louder if I rev it.
I know its not a belt because I've previously heard the noise a bad belt can make (More of a squeal). I have had it looked at quickly and the way I describe it a local man I know who does deal with cars thinks It may be the water pump. As if only happens after I've been driving the car for approx 20 minutes or more. Its as quiet as a mouse when first started after its been unused for a while.

I am trying to learn more and more about cars and have bought a haynes manual but It hasn't come through yet, so if anyone does think they know the problem could you let me know any checks I could do to eliminate some problems and also were to get certain parts (and the name of parts) and if anyone fancies taking the time to let me know how to change it, it would be much appreciated.

Thanks for your time, I look forward to getting some full and good responses.
Thanks Alot.

Could be water pump or alternator bearings if not a belt, although belts can squeal differently, a cambelt will sound different to an alternator belt.
Always like someone willing to learn!

I shall list the candidates for this sort of whine (if you are certain it is not a belt)...

1) Cambelt tensioner bearing
2) Water pump
3) Alternator bearings (usually from a too-tight auxillary belt)

I presume the weekly levels checks are not showing any losses, therefore

First step to resolving the issue.

Get car warm to the point where the noise starts.

Remove alternator belt.

Run car again, the alternator light will be on and make sure you use no electrics.

If the noise is gone, its an alternator problem.

Noise still there, needs further investigation.

Probably cambelt tensioner or water pump.

Cheers

SPD

A cam belt will whine if the teeth are binding.

You said the belt is new - but which one and did the noise start just after the new belt was fitted. My bets are on the cam belt or one of its cogged wheels