I drove the car (2013 elegance  2.0L tdi 170bhp 6speed dsg 4x4) last nigh from cold less than 3miles got out of car locked it up and heard the electric fan was on i have never heard it before jumped back into car started it up to check temp gauge and it was just up to normal running temp right in the middle. drove car back to my house less than 3 miles switched car off took keys out and fans where still on again i had to go some where else about 8miles away got back and fan had stopped.

i thought the fan doe not come on unless the temp gets high? 

dose anyone know why the fan would come on even if the engine is only at normal running temp even when i turn the engine off?

has anyone else had a problem like this?

cheers kev    

 

 

   

Probably a DPF regen

 

It's completely normal for the fan to run on if you turn the car off mid-regen. It's nothing to be concerned about unless it starts happening on a frequent basis

thanks for reply langers2k i didnt know they could regen when just pottering around town, i thought you needed to get them on the motorway for a decent run to get the temp up ?

come to think about it now i did lift the bonnet just to check things looked ok under there the only thing i could feel was the sheald on top of the turbo seamed to be a bit worm and the engine was just coming up to ruining temp i.e bang on the middle and to be honest i make the same distance trip pretty regular its one of my daughters house and over this cold spell we are getting, same trip the temp needle is only on 1/4 so i was a little surprised  to see it was on 1/2 witch is the cars normal running temp?

cheers kev!

 

There are passive, active and service regens.

- Passive regens will happen 'naturally' if there is sufficient heat to burn the soot off.

- Active regens are when the ECU injects extra fuel to get the DPF warm enough to burn the soot off.

- Service regens are triggered by diagnostic equipment.

 

Typically only high load driving will get the DPF hot enough to cause a passive regen. Motorway driving, towing or steep terrain can help. Some claim they never happen but I certainly saw them on my CR140.

 

In your case, I expect the ECU had triggered an active regen due to soot levels, these are normal and most of the time you won't notice them if it happens during a drive. You might have a slightly higher idle and increased fuel use so nothing super obvious whilst on the move. They happen every ~100-400 miles depending on driving style and if the car has had the emissions fix.

 

If the regen hadn't completed when you turned the engine off, the fans stay on to help dump the extra heat in the DPF from the active regen.

 

It's quite possible it still hadn't completed after your second drive. However, after your third drive it had either completed or dropped the soot to an acceptable level

 

It wouldn't surprise me if a car wants to perform an active regen, it can tweak the fuelling to get the engine to warm up more quickly too.

thanks for the help buddy!