Loud knocking that may come from AC

[friviera]

Hello,

I have a 2020 i3 since December, 4 times since I got the car I heard a loud knocking noise, and feeling a small shock coming from the rear of the car,
the car was stopped or parked so it's not coming from the movement/engine.
The first time it happened was when Bimmercode restarted the AC, when it happened I thought a pinecone fell on the car.
Then it happened without explanation 2 other times.
It happened again today, I thought someone with a bike hit the car.
It's like "chonk".

I went to BMW a few weeks ago, from the area the noise was coming they confirmed this could come from the AC, they did a quick check of the AC thinking maybe it was the compressor seizing
but without finding anything and it's running fine.

I checked today with Bimmerlink after I heard that noise, there is no error visible.
The car has a heatpump, the AC is always on automatic mode and used daily. (for 3 days now we went from heating to cooling the car).

Does somebody know what this could be ?

Thanks a lot.

 

[friviera]

For anyone who would find this after searching this symptoms, it was the AC compressor failing, this has to be replaced asap as the battery isn't cooled anymore.
The car had to be driven slowly to avoid battery overheating and the car was immediately immobilized by the BMW workshop until this was fixed.

 

[Paul4A]

How much are BMW charging for a new compressor installation?

 

[friviera]

I'm in France so this is French prices,
compressor: 1533€
mounting kit: 82€
screws: 6€
R1234yf fluid:26€
misc parts: 204€
labor 929€ ( ISTA diag,car test,AC test, removal and installation of the compressor, AC circuitry cleaning, vacuum and filling of the AC, car test, on road test)
(labor is 13,90€/5min of work)

The total is 2780€

 

[Simoni3]

i have had similar done in UK bit less in cost BMW dealer

def tempted to take it to a local EV / car air con mechanic