Funny electrical warning sound, dealer has no idea

[Zchryst]

Anyone have any ideas?  It’s located in the front left (US driver side) engine compartment. 

 

It sounds for about two hours while it’s parked after driving enough to bring it to operating temperature.  It doesn’t start right away, maybe 30 minutes after it’s parked.

 

Thanks all!

 

Zach

[Greydog]

Morning Zach, 

Welcome to the Forum

When you say Dealer is it a BMW Dealer? if it is then that really doesn't give much confidence fr the future?

The noise could be a turbo cooling pumps moving oil and coolant around ? just a guess but something similar I would suspect 

Dave

[Zchryst]

Yes, local BMW dealer. Tell me about it!  It’s not just the dealer who leaves me with little faith, the service manager sent it to the BMW field rep who came back with this...

 

“My first guess would be to check the crankcase pressure. It almost sounds like air escaping past the front crank seal.

 

Otherwise the only way to pinpoint the noise is to catch it happening.”

 

Doesnt sound right to me at all, so I came to this group figuring I’d get answered/thoughts from people who aren’t just looking to sell me new tires when my tread still has 30k miles left. 

 

Your answer makes the most sense of anything I’ve heard yet. Thanks!

[Greydog]

Hi Zach

I just had a quick check on www.realoem.com BMW parts site (put the last 7 digits of your Vin in the search box it will bring up your model) and www.newtis.info this is a technical information site used by Dealers (but not yours it seems?) Your engine does has an electric coolant pump, so it makes sense that after engine switch off the coolant circulates to aid turbo cooling, time would probably be sensor driven until below a certain temp.

I am not certain but it seems logical to me

Dave