Humming/Droning noise - United Bimmer Community

**frem** · 06-01-2011, 03:56 PM

Hi frustrated Newbie here!

My 2003 E46 Ci has developed a noise which I can only describe as a continous humming/droning noise coming from the front when on the move.

Firstly, It sounded like road noise coming from the tyres but swapped them with the rear ones to no avail.

Secondly, it doesn't increase/decrease with speed, so I'm thinking maybe gearbox? Its a steptronic and I don't have any trouble changing up or down either manually or automatically, no clunking sounds etc. So I'm at my wits end!!

Any thoughts?

Don't want to go rushing to the dealer just yet. Many thanks

**Manolito** · 06-02-2011, 12:32 AM

I don't think I fully understand.

The noise only happens when the car is moving forward, but it does not change in volume or pitch with road speed or engine speed?

What about when you turn the steering wheel?

The first thing that comes to mind is a hydraulic pump, but that would make noise whenever the car is running, whether it is moving or not, and would change pitch with engine speed. If it turns out to be the hydraulic pump in the power steering, many of us have been able to quiet those down with fresh fluid. It is a good idea to pull out the reservoir and clean the screen as well. You you are going to pull out the reservoir, you may as well replace the power steering hoses. They are probably leaking anyway, right?

**frem** · 06-03-2011, 10:42 AM

Thanks for your suggestion but its not the power steering, no noise when I turn the wheel either.
It's an awkward one, I know, but the way I can describe it is that it sounds as if its fitted with a CVT box, like those old DAF's!

Big Evil · 07-17-2011, 02:37 PM

Gonna need more info. Noises/rattles can be a real pain to diag and almost impossible with something unusual and not having the car itself to test.

No change in pitch or volume, just a constant hum from the front end while moving? My money would be on a wheel bearing issue at this point

**frem** · 07-20-2011, 02:13 PM

I've stuck my head under the bonnet and had a good look round. The only thing I have noticed that is out of the ordinary, and you can appreciate how difficult it is to see, is that number the nearest downpipe from the exhaust manifold is nearly white in colour whereas the others appear to be black.
My assumption is that the manifold is blowing somewhat, hence the change in colour and the lack of change in noise volume?