Hum / Resonance noise when accelerating

[BenD]

Hi, 

new to the forum and am looking for anyone who has had this problem with a Galaxy.

i have a 2014 2.0tdci 163 titanium. I have noticed a noise when accelerating, if I'm rolling along in 3rd/4th/5th or 6th and the RPM is around 1500 and accelerate hard (press foot to the floor or nearly to the floor) as the revs start to increase, I get a groan/hum/resonance noise from under the bonnet. This only happens when the engine is at it's warm running temperature and the aircon is ON. Turn off the aircon and it doesn't do it

It has been to be ford dealer under warranty and they have replaced the EGR valve, a pulley on the aux drive belt and changed the aircon gas pressure per a mod which ford released. Still no joy.

now I'm getting the usual from them that it's clearly a characteristic of the vehicle.... which I don't believe and they don't have another to let me have a go in....

 

any ideas or has anyone had this issue before and fixed it? Do they all do it?

thanks for any help.

Ben