Over the last few weeks when the weather has been a lot colder, I have noticed a whining noise on start up. It appears to be coming from the front nearside of the engine bay. I think it's to do with power steering, as it seems to sound louder each time the steering wheel is turned and quietens down again on the straight ahead although still audible.

The noise disappears after a few minutes when the engine has started to warm up and it doesn't seem to have to reach the normal operating temperature.