Metallic Crackling Noise in 2015 Z4

[SanfordZ4]

Hello All,
Just wondering if any one knows the root cause of this strange metallic noise. It typically occurs only on a cold morning. We live in Florida, so it does not really get cold. 2015 BMW Z4.
I have included the Time stamp for the noise in the video:

Start - End
9 - 15
21-23
32-36

Thanks in Advance

[bigendbob]

Z4 cabins can full of all sorts of noises.
Best thing i did was to spray some silicone lubricant in every single plastic joint in cabin.
Cured a irritating noise that sounded like small stones hitting windshield, it was the plastic flexing.
Also stuck some rubber pads behind the sun visors, they tap against the plastic.

[SanfordZ4]

thanks. I am scheduled to take it to the dealer for service. Will update once we figure out the root cause. I have had Toyota's and Honda's for years and they never make stupid noise like these. Can't believe BMW cars this flimsy..

[SanfordZ4]

one of the mechanic mentioned that the noise could be related to catalytic convertor on the verge of going bad. i was looking for image (of inside) of catalytic convertor to see if it has plates or similar parts that are loose and stiffen up once the car has run for a while... that might logically make sense.

2 questions:
1. has anyone else had similar experience
2. would anyone have an image of inside of CC used in this model

thanks

[MarinerZ4C]

While I can't say it's not the cat, I think the suggestion of a bad cat is alarmist - especially if miles are low. This seems focusing on the least likely and most expensive possibility first.

Does it only happen when the car is moving? Does it ever happen at idle ? Have you started the car from cold with the hood up and listened for the same noise? If it is only at speed and no bad noises from the engine bay, then it's likely to be something like the kind of rattle suggested by Bob.

Your cell phone may not pick up the sounds just the way you hear them, but I didn't think of it as metallic (maybe that's just the video ?). I have a pickup truck with a similar rattle that started only when we went from Summer into its first Winter. I did what I hoped was the final permanent fix with felt, and now that felt has apparently vibrated out of position or worn down, so it's rattling again. Hope yours is that simple.

Hang in there - you'll find it ! Get a passenger to help by riding along and touching or pressing on vents or other pieces that seem close to the noise source. If 2nd person cannot be arranged, try placing your phone in different spots to record the noise and help you pinpoint location.

P.S. What engine and transmission ?