Cooling down noises

[theresanothersteve]

2015 118TSI Jetta, 5,000kms on the clock...

A few minutes after parking in the shed (warm motor, just done over 30Ks) there is an intermittent sound (about every 30 seconds) that sounds for all the world like a small drill bit being sharpened. Lasts for a couple of seconds each time.

Any clues what it might be?

[LukePolo]

From memory it's the supercharger winding down in conjunction with the vacuum water pump letting water into the turbo to cool it down after a drive instead of a turbo timer.. Correct me if i'm wrong!

[Rawcpoppa]

Is it a hissing sound? Typically cooling down sound comes across like metallic sounds. I used to get metallic creaking sounds when my Jetta was new (less than 10,000 km). I believe it came from metal shrinkage as it cooled.

I now get a hissing sound from the mechatronic unit located to the front right side of the car when one is facing it. This is separate from the fans running for at least 15 seconds after shutting the engine off and these produce a sound of their own as well.

[Haydennedyah]

Probably normal but just tale it to dealer to check

[theresanothersteve]

From memory it's the supercharger winding down in conjunction with the vacuum water pump letting water into the turbo to cool it down after a drive instead of a turbo timer.. Correct me if i'm wrong!

Don't think it would be the supercharger, that's driven by the motor so would stop turning when the motor stops.

Is it a hissing sound? Typically cooling down sound comes across like metallic sounds. I used to get metallic creaking sounds when my Jetta was new (less than 10,000 km). I believe it came from metal shrinkage as it cooled.

I now get a hissing sound from the mechatronic unit located to the front right side of the car when one is facing it. This is separate from the fans running for at least 15 seconds after shutting the engine off and these produce a sound of their own as well.

Definitely a metallic sound - imagine the 'tring' sound a small drill bit as it touches a grinding wheel to be sharpened.

Thanks, blokes, I'll give the service department a ring...