Radiator fan

[DotNetDude]

The radiator fan on my 40TDI often stays on very loud, and for a very long time after parking the car. I'm guessing its normal, to cool the engine down, but it must be running for a good 15-20 minutes, which seems excessive. Its also smells hot. When it first did it I thought is was just because everything was new, but 3 months later and it still smells hot. Is that normal?

Thanks

 

[DaveW]

I think its part of the DPF re-gen cycle, happens to my C8 and also to my previous C7/C7.5's

 

[cuke2u]

Yep a regeneration will cause this https://www.theaa.com/driving-advice/fuels-environment/diesel-particulate-filters

 

[ChetA6]

Yes definitely part of the regen cycle, has anybody noticed the car running significantly better/smoother/more boost when on one?

 

[DaveW]

Yes definitely part of the regen cycle, has anybody noticed the car running significantly better/smoother/more boost when on one?

Not really, just a lumpy tick over

 

[ascr]

Not really, just a lumpy tick over

Definitely noticeable in my C7 bitdi. Agree it felt more rough but really noticeable on acceleration, don't think it was actually any quicker, just felt more responsive to inputs, as if it was running a richer mixture if you know what I mean.

 

[DotNetDude]

Thanks for the comments.
Actually I also searched and found a good article which describes the symptoms very well: https://georgetownvw.wordpress.com/...ooling-fan-run-after-shutting-the-engine-off/.
I had a DPF cycle this morning; I had a short 15min journey and then parked up for 5 minutes. When I came back to the car the fan was running. Over the next 15 minutes, I couldn't notice any discernible difference in any way, with the drive of the car - it was neither quicker, slower, lumpy. Nothing...

 

[elan2s]

Not sure if it is just because the car is new but I am noticing that my car is doing many more, albeit they seem shorter, regeneration cycles than either of my previous C7s. Think people's feeling of a change in driving characteristics may be due to the car idling at about 1000rpm rather than 800 so there is aquicker initial pickup when accelerating