GTD Fan on after engine stopped

[adekil]

I think I have read that on TDIs post 2009 its normal for the fan to sometimes stay on after the engine is switched off, is this true?

Had the GTD for 4 weeks now and has done this 3 times that I've noticed and lasts around 5 minutes, is that normal behaviour?

[p3asa]

Yeah. My last Golfs fans lasted a full 14 minutes after I parked up and went in the house!!
It is more likely to do this if a regen is or was taking place.

[Sootchucker]

It's to do with an Active Regen taking place on the DPF (Diesel particulate Filter), which is located on the outlet of the exhaust manifold and is designed to burn off the soot particles that are trapped during the normal operation of the DPF. As to do this, the ECU needs to substantially raise the exhaust temperatures, then if you were in the middle of an Active regen when you turned off the ignition, then the fan will continue to run to cool everything down again.

[adekil]

ok cool, thanks!

[AlanH]

So how do you know when a Regen is taking place when driving?

[ajmoir36]

So how do you know when a Regen is taking place when driving?

If its like the old mk6 it will tell you to change down if the revs go below 1500rpms or at idle it will be around 1000rpm.

[AlanH]

Thanks for that. I was probably expecting something like a computer-generated voice telling me "Stand by for Active Regen in 5...4...3..."  Maybe on the Mk8?

[simonpolly]

Funny you should mention this,i took my Sharan to be checked on monday for the same thing,seems the fan can come on and stay on for upto 40 mins after you turn the engine off  .I never get any warning lights on mine saying it needs doing or is about to do it but it only does it intermittently and on reading the manual it says if you get a warning light drive the car in 4th gear for 15 mins and that should clear it.