Engine bay noise after shutdown - MKV GTI

[Helipilot]

Guys, has anyone noticed a relatively quiet humming noise (similar to an electric motor running) after shutting down the engine ? It seems to continue for 5 -10 minutes after turning off the key and is usually only apparent in the quiet of the garage - most often after returning from a run down the freeway.

Is this a thermatic fan or oil pump for the turbo perhaps ?

[CatonaPC©]

Could be the fan, but that would be louder than a hum. Does is happen only on a warm day?

[turboveedubb]

I've heard that it's a mechanism to cool off the turbo. (Kind of like a turbo timer). The fan noise is much much louder than the sound that you're probably hearing and as you said, it's only noticable when it's almost dead quiet.

[Blitzen]

Its an electric water pump suppling coolant to the Turbo after shut down.

[zz2]

its the sound of a secondary coolant pump that pumps the fluid backwards through the engine after its been shut down to cool down the turbo.

im not sure how effective it is in comparison to a turbo timer.
that said if i have been driving it hard prior to engine shut off i will still let my engine idle for a minute or so before shutting it off.

[CatonaPC©]

its the sound of a secondary coolant pump that pumps the fluid backwards through the engine after its been shut down to cool down the turbo.

im not sure how effective it is in comparison to a turbo timer.
that said if i have been driving it hard prior to engine shut off i will still let my engine idle for a minute or so before shutting it off.

Is this mentioned in the manual? Does it apply to TDI as well, as I haven't heard anything yet.

[zz2]

im pretty sure its mentioned in the manual some where but i actually found that out ages ago on the golfmk.com forum.

not sure if theres a similar system on the TDi engines.
also you have to remember the exhaust gas temperatures on a diesel are significantly cooler than that of a petrol (hence why at the moment only diesels can have variable geometry turbos... well cept for the new 911 turbo)

[Vicbitter]

Is this mentioned in the manual? Does it apply to TDI as well, as I haven't heard anything yet.

There is a similar system for the tdi's.
I got the tdi engine and let it idle for 15-30 seconds when i get home after cruising on 100km'h.
It is a pump cooling the turbo after shutdown. Most its been on is about 1 min, usually 30sec though.

[Helipilot]

Thanks guys, mystery solved

[qsilverza]

Don't know if it is only for turbo cars, as I have a similar noise in my Bora.

Possibly as you say to pump around the engine to cool down ?

And we used to get it in an older Audi a4 2.6 and a newer a6 2.4