My Car has been making a noise that comes and goes. It seems to be dependent on the speed of the engine and coming from under the hood. It can come for an hour and then dissapear for a week, then come back etc.
Toyota Yaris 2008
4 cylinder, 1.5L engine
Attached is an MP3 of the noise, you may have to turn up the volume to hear as it isn’t super loud.
Note: seems to happen more often in colder weather. It sometimes happens right from startup, but other times it doesn’t start until after half an hour on the road.