[Yuri Stark]

Hi guys,

I have this strange noise on cold starts, at about 30-60 seconds after the start on my 540i. It can be heard right at the beginning of the video. It sound like a low pitched irregular turbo flutter.

https://youtube.com/shorts/kqsqOsUjpBM

I've talked to a bunch of mechanics, went to the dealership but no one could identify what the problem could be. Also, I've talked to a bunch of B58 owners as well and no one came across this noise.

There are no codes, the logs are within the correct ranges, the car drives just fine. It is not one of the pulleys or the tensioner. The car is on stock map with pump fuel.

My guess is it might be the intercooler electrical pump, or one of the electric water pumps around the intake manifold. (There is one more pump under the left headlight) I do not have any visible coolant leaks though, so this theory has its' doubts.

Before I was going to take half of the car apart I am curios about your thoughts

Any information on this matter could be useful.
Thanks!

[I3LaZeN]

Hmmm never heard that before. Curious what it could be.

[Yuri Stark]

Me and you both, brother

[tjbuggy2b]

Are you talking about the gurgling sound. First thing that comes to mind is air in the coolant line but I'd imagine you'd be running a little warm, if that was the case.

[Yuri Stark]

Originally Posted by tjbuggy2b

Are you talking about the gurgling sound. First thing that comes to mind is air in the coolant line but I'd imagine you'd be running a little warm, if that was the case.

Never had a problem with overheating, although my thoughts exactly, that it is a cooling related noise. I've checked for leaks and air and all is good. I'm soon to replace the coolant as it has 50k miles and 6 years so it would be good to refresh it.

I'll keep you posted if no one else comes up with some news