This whistle isn't the regular intake sound. It sounds like a tiny blow off valve. You can control the whistle with your foot. Meaning, drive down the road, no whistle. Push in the throtle 1/2 a centimeter deeper, whistle starts. Let out throtle 1/2 centimeter or push it in a 1/2 centimeter more and it goes away.
Occurs at all temperatures.
Oi. Not lovable, just annoying.