Mondeo LX 2.3 petrol - Mazda L3 motor - engine whine

[WagonWheel]

I've test driven two Mondeo LX MC wagons, both 2.3 petrol versions which use the Mazda L3/Ford Duratec motor, and noticed an engine whine in both, one more prominent than the other (making it way more noticeable). The noise sort of sounds like a car reversing and identical to the whine in this video of a 2004 Mazda 6 in drive (same 2.3 motor): https://m.youtube.com/watch?v=TmVbQoDTZIg

Now, I don't know if this is just a normal sound for this motor or whether something is wrong e.g. transmission pump?. Anyone experienced this in the petrol LX or Zetec or know what causes it?

Apart from the noise, the cars felt fine and drove well.