Had the  car 2 week snow (I've done 2.2k miles so far).

 

For the first time today the intercooler remained on (ignition off) after a journey for about 2 mins, 170 miles which isn't particularly long for me.

 

I then left the car for 1 hour (its 4 degrees C) then needed to pick the kids up from a party,  about a 15 min trip, 6 miles and agin the intercooler remained on for 2-3 minutes.

 

Any cause for concern, is this normal, why hasn't it done this before with similar / longer journeys?

 

Any thoughts or input welcome 

 

 

I assume you mean the fans were running?

 

It sounds like you interrupted a regen, the fans running on is perfectly normal in these circumstances 

As above it is due to it regenning. Were the idle revs higher than usual before you switched it off?

fans were running yes, assumed it to be the intercooler...

 

Would have thought it would have regenned during the long journey ( I was >70mph all up the M6 toll)?

 

Didn't notice higher revs but I did have it in normal as opposed to eco which is my norm.

 

Will be running it from stoke to leeds tomorrow so should finish regen then once upto temp... might treat it to some extra rpm once fully warm.

 

 

Don't forget that

1. The ECM automatically initiates an active regeneration if there has been no regeneration, or no successful regeneration, in the last 465 miles, regardless of the load condition of the diesel particulate filter.
2. “The charge pressure is adapted so that during regeneration torque does not change noticeably for the driver.”

The regen system in the S3 is quite complex. Above is taken from the Self Study Programme for the engine  

As above, it’s normal on any car fitted with a DPF in order to prevent fires.  The DPF temperature gets very high (it is burning soot) so the engine bay fans run to stop damage to the car when stationery - or switched off mid-cycle.