CDti Humming Noise
 

Hi everyone, I have 2004 conne cdti. I was doing some jobs on the car today and could hear a humming noise coming from somewhere. Ignition is off. FBH is ok, under bonnet pump is ok. I can't seem to trace where it's coming from. I thought at first it was coming from underneath the air filter housing, then closed the bonnet and listened through the grill still there. Thought it might be coming from the alternator, although the ignition is off. Has anyone come across this or any ideas, please.

You need to listen to various areas using a stethoscope or a long screwdriver against your ear, that should highlight any strange sounds.

Humming Noise.
 

Thanks for that. I went out this morning and the noise is still there. Strange.

Bees, possibly?

sometimes the sat nav in the boot have been prone to staying on,could be disc whirring in that (if you have sat nav).

Bee's Buzz not Hum :D
I'm not sure you would hear the sat nav in the boot via the front grill :D
I would agree you are on the right track with the alternator though!
I had a Rover 800 that gave off a high pitched tone when switched off. and would drain the battery in less than 2 days if car not used. IIRC it was the diodes at fault.

Humming Noise.
 

Thanks for all the replies. I've ordered a stethoscope and will see if that picks it up. I will also unplug the alternator to see if that the problem. If it is I presume it's faulty and will need replacing.

Unplugging the alternator is not enough, when mine developed a fault I had to remove the heavy lead that is bolted on too as this is where the output is and mine was a diode fault.

Humming Noise.
 

Hi everyone, Found the fault which is the alternator. Fortunately, I've got a parts warranty on it so no dirty hands for me. Thanks again for all the tips and advice.