2010 135i n54 strange noise

[Tireman2465]

Thank you in advance for any and all who might be able to help.
I recently purchased a used 135i , love the car. I can't drive it without grinning. However, I have noticed recently a strange bird chirping sound that is intermittent when at idle and operating temp. My first thought was a pulley , idler tensioner maybe even an alternator, the noise is fleeting and I have not been able to pinpoint a specific area under the hood, Today I noticed when I parked in the garage the noise happened after I turned the car off, So much for pulleys or alternator.
Writing this, I realize it could well be the cooling fan

[MarcoZandrini]

Do you live near San Juan Capistrano? A joke, a bad joke.

Ok, if the chirp happens with the engine off then there’s some auxiliary subsystem that’s likely causing the noise. The first thing to do is to use your smartphone to record the noise. Then set up a YouTube account and upload the recording. Lastly, paste the link into your response.