Just curious.... about 2 seconds after turning off the engine, there is a "thwap" sound from the engine compartment. It sounds exactly like the sound when the trunk (convertible) is opened with the release switch. Some sort of cut-off for the super charger?

 

Sounds like the classic worn supercharger coupler/torsion isolator issue, search around under "torsion isolator" and "supercharger coupler".

 

It has done it since the day I purchased the car new.

 

+1
Always thought the squirrels were closing the door to the treadmill

 

+2. Happens several seconds after the engine is shut down, so not a part of the engine operation. Sounds like it comes from the center or right side of engine compartment, like a diverter gate of some kind closing. It's normal, so don't worry about it.




Edit: Oh...Oh...Oh! It might be the valves on the adjustable suspension changing position after losing electrical power.

 

Thanks Unhingd! I have not been worried as it sounds like something 'closing.' Just my geeky self being curious. Not sure about the suspension valves as aren't they in each of the 4 spring dampeners?

 

Yes they are. However, trying to triangulate external sources of noise from inside the cabin is always challenging.

 

do you agree that it sounds exactly like the trunk lid unlatching only under the hood?

 

Yes, very similar.

 

i have the same noise, don't worry about it

 

Thanks Nati!

 

There is a set of louvers in front of the radiator that help the engine get up to temp quicker. You’re just hearing them close when you turn the car off. The F-Pace has the same setup and I hear the same sound. Totally normal.