2013 520i rev hunting issue

[furbz]

hi all,

i just wanted to find out if anyone knows what might be causing a issue i am experiencing with my car.

i have attached a youtube clip of my car misbehaving.

essentially on first start in the morning the car idles high(i assume a warming up thing), however during this period the car rev hunts. this never used to happen before.
If I try drive the car before this rev hunting occurs the car jerks and sometimes nearly stalls.
It used to be intermittent, however it now seems to do it every first start of the day. Strange thing is, after driving it to work, then having it sit for a good number of hours the problem does not reoccur. It only has a issue when on first initial start.

of course bmw diagnostics have come back showing no issues. :smashScreen:

any help would be appreciated!
the car has 28000km on the odo

here is the link:

Regards
Furbz

 

[sash]

was the car on diagnostics when cold?

 

[car_fanatic]

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[furbz]

as far as i know yes.
they had the car overnight so i assume they checked it correctly.
although one should never assume.

car goes back in tomorrow...

 

[sash]

i would like to be there when doing the test.., half the time the techies dont realise the problem even thought it is doing it in front of them.

 

[furbz]

ok, so got the manager involved and BMW was able to replicate the issue.
turns out it was a faulty engine thermostat.
issue resolved!

 

[furbz]

spoke too soon!

car started rev hunting again this morning.
in addition i now have a tapping noise accompanied by a water sloshing noise coming from the dash?
very strange