whirring noise on acceleration but stops with gear change

My c3 has developed a strange whirring noise on acceleration but stops with gear change. Not noticable on higher gear. People have commented that it now sounds like an electic car. Where do i start with diagnosing the problem?. Starts fine. Drives fine.
Dont want to take to a garage if its a fixer at home.

c3wazz1 wrote:My c3 has developed a strange whirring noise on acceleration but stops with gear change. Not noticable on higher gear. People have commented that it now sounds like an electic car. Where do i start with diagnosing the problem?. Starts fine. Drives fine.
Dont want to take to a garage if its a fixer at home.

Hi c3wazz1, if the pitch changes with engine RPM, then its part of the engine and if it changes only with road speed, then its going to be part of the drive train.

As you say it stops when changing gear, or more importantly while depressing the clutch?, it could be clutch related.

If you rev the engine in neutral at a stand still does the sound change? can you even hear it?

When in neutral and rev the engine i get the same whirring noise. So defo know its not the wheel bearings.

As C3CAR asked above, does the whirring change speed as the engine speed changes or does it just start at a certain engine speed and stay the same. Also any increase in loudness with changing revs?

Is it definitely a mechanical noise, could it be electrical through the speakers.

If the whirring happens when the car is in neutral and stationary, can you get someone to rev the engine while you have a listen, inside and out, to determine where the noise is coming from. Be careful if you open the bonnet with the engine running.

Will have a check tomorrow but can only hear it from the outside of the car. Could keep the windows closed and ignore it but dont think that is a sensible solution lol .

Had the bonnet up today. Noise seems to be coming from the drivers side of the engine... alternator area. Tried to remove the alternator belt to see if the noise stops. But cannot remove seems to be jammed..

c3wazz1 wrote:Had the bonnet up today. Noise seems to be coming from the drivers side of the engine... alternator area. Tried to remove the alternator belt to see if the noise stops. But cannot remove seems to be jammed..

There are 2 systems of tensioner for the aircon/alternator belt. You could have either.

One is an automatic tensioner and the other a manual tensioner, you will need to identify which you have before the belt can be removed.

If its the manual adjuster, there are several bolts to slacken off, if its the automatic adjuster then you just need a spanner to release the spring pressure.

The Haynes Manual (from Amazon) has a page devoted to the procedure for replacing both those belts (it involves removing the inner wheel arch to gain access).

c3wazz1 wrote:Could keep the windows closed and ignore it but dont think that is a sensible solution lol .

I agree, not a sensible solution. The sound is warning you to do some maintenance before some major failure. As you suggest, quite possibly the alternator bearing.

Does the car also have air-conditioning?