Technical Constant chirping sound while on the move

[Noah500]

Ever since I've had my 500 (about 18 months) I've been annoyed by a constant chirping/rattling/whistling sound which is very intrusive and loud. I know these engines aren't the quietest around but this noise seems to kick in mostly when the car is on the move from a low speed and doesn't vary based on either engine speed or road speed.

Now that I've addressed some of the more pressing other niggles, I would like to solve this one. FYI it seems to be more noticeable inside the car than from behind with the engine lid open, but from inside it does appear come from behind the rear bulkhead.

Any ideas of what could be causing it? I did see that the starter and throttle cables can also against each other and against the edge of the hole in the metal that they go through from the engine side but I've covered the relevant sections of those cables with some split rubber hose and the noise is still the same. I can't see anything else obvious in the engine bay...

Thanks in advance for any tips.

 

[Noah500]

Oops! - culprit found: engine lid luggage rack was a bit to loose, allowing the top brackets, which just hook over the top edge of the lid, to rattle despite stick-on foam tape... Fixed by removing the rack, bending the brackets a bit in the vice, and refitting, this time with extra U-trim over the lips of the brackets

 

[Goldnrust]

That was an easy and importantly free fix then! we like those!