High pitched whine from behind grill

I notice the same kind of noise on my Renault Koleos . It's also powered by a turbo diesel, 2ltr 150hp.
The noise is more a buzzing sound that is going on for about about 2 min after engine stop.
Never worried about it

I've found where it's coming from, just don't yet know what the component is.
It looks like a linear solenoid of some description, and if so, the noise could be coming from the coil windings vibrating.
As the noise stops there is a click, which must be the solenoid de-energising and whatever it is pushing or pulling springing back into place.



Would be interesting to hear how many people don't have this noise coming from their Evoque. But I guess if they don't have the noise they won't be reading this thread :/

The noise starts when I-
1. Unlock the car
2. when the noise stops it starts again when I open the door
3. then when it goes off again, it comes on when I hit the brake pedal.

So I suspect it might have something to do with the vehicle electronics preparing the engine for an engine start.
Still don't think it should be buzzing though...

Could it be energising the HP fuel pump for the common rail system?

It's the high pressure water coolant pump,as the cylinder head gets a lot hotter than the rest of the engine, this needs to be cooled for longer, therefore this pump is set to run after the car is switched off.

My citreon nemo 1.2van does it too.

(08-11-2013 06:09pm)da22a1 Wrote:  I've found where it's coming from, just don't yet know what the component is.
It looks like a linear solenoid of some description, and if so, the noise could be coming from the coil windings vibrating.
As the noise stops there is a click, which must be the solenoid de-energising and whatever it is pushing or pulling springing back into place.



Would be interesting to hear how many people don't have this noise coming from their Evoque. But I guess if they don't have the noise they won't be reading this thread :/

The noise starts when I-
1. Unlock the car
2. when the noise stops it starts again when I open the door
3. then when it goes off again, it comes on when I hit the brake pedal.

So I suspect it might have something to do with the vehicle electronics preparing the engine for an engine start.
Still don't think it should be buzzing though...

Thanks for the Pic da22a1, Can't make out what that is, it could well be a solenoid, but I don't believe a solenoid should make that amount of whine, it maybe this solenoid is related to the EGR Valve or water pressurisation as suggested and if it is a High Pressure Electric pump and the solenoid maybe re-directs the coolant... something like that....

Mike, certainly could be a High Pressure pump, but why does it make this noise when is engine off and stone cold if you think it's for additional cooling? Surely for cooling by an electric pump it would turn on when temperatures were getting hot, for efficiency.

What would be good to know is if someone with a Petrol engine has this noise...

On modern cars HP fuel pumps are located inside or very close to the fuel tank, very hard to hear them

(10-11-2013 10:16pm)Mike Wrote:  It's the high pressure water coolant pump,as the cylinder head gets a lot hotter than the rest of the engine, this needs to be cooled for longer, therefore this pump is set to run after the car is switched off.

Sounds like a reasonable assumption as the turbo is water cooled and would benefit from the extra cooling from the hp pump

I had a look under the bonnet of my Renault and performed some engine stops. As soon as the buzzing sound ceased several valves at different places shut or opened with a clicking sound.

My conclusion is that it must be a timer deactivating the valves after engine shut down