Loud buzzing sound

56 plate td6 - just started making very loud continuous buzzing sound coming from in front of the driver - even continued making the noise when I switched everything of for at least a few minutes - then died down slowly - but still made it a little on restarting the engine - hope someone has some ideas on this no errors shown on screen - thanks.

It could be the ECU cooling fan. The bearings start to fail after a while. I'm not sure where exactly this lives on the td6. It's quite to replace or you could try a squirt of graphite lubricant.

That would have been my guess on my 4.4 it's drivers side of the engine compartment at the front and is a big black plastic box and runs even if I just unlock the car

Thanks for the above - not doing it today - will wait till it does it again.