Engine fan over run on T6.1

[Rowls1958]

The engine fan on my 2020 T6.1 California Ocean continues to run very noisily for over 5 minutes after turning off the ignition. This happens on both long and short runs - is this normal ?

 

[Loz]

Is it every journey? if not then it's regeneration not completing.
The ECU doesn't know how far you intend to drive so I often find that it will start a regeneration just before I get home and then will do one next time I go out but not until it is up to temperature so you can get into a cycle of a regeneration every time you go out.
I have learnt to feel when it is doing it now and if still doing it when I pull up I keep the engine running on a fast idle until it finishes.(you hear a very slight lift in rpm and when you take your foot off, the tick-over has returned to 950, let it tick over for another minute and you don’t get the fans going mad)

 

[Rowls1958]

I think it is every journey but will double check. What is regeneration ? Cheers

 

[Loz]

I think it is every journey but will double check. What is regeneration? Cheers

The vehicle is fitted with a Particulate filter that slowly fills up with soot and this has to be burnt off otherwise it would get blocked up.
The Engine Control unit uses a differential pressure sensor to measure the difference in pressure between the inlet and outlet. When it reaches a certain level of blockage, it runs a cycle that injects fuel in the exhaust cycle and heats up the turbo and the particulate filter to about 700deg where the build-up of ash is burnt off.
During this cycle, the tick-over raises from 950 to about 1000rpm and the engine feels a bit rough.

See page 28 of the attached.

 

[Rowls1958]

Learn something new every day......glad I just extended the factory warranty to 5 yrs 150k miles...... £640 seems a bargain...

 

[OGII]

I have learnt to feel when it is doing it now and if still doing it when I pull up I keep the engine running on a fast idle until it finishes.

A recent conversation with a VW Assist technician about looking after EGR suggested looking out for idling revs of around 1100 rpm at the end of a journey. If so leave the engine running or drive around the block until they drop back to normal when the regen will have finished naturally.

 

[willwander]

The regen seems to work via the satnav, it always kicks in as I pull onto my drive

 

[paul_f]

The vehicle is fitted with a Particulate filter that slowly fills up with ash and this has to be burnt off otherwise it would get blocked up.

Very close, but it actually fills with soot and then this is burnt off leaving a small amount of ash.
The ash gradually builds up, but once full the filter has to be replaced (dealer) or removed and backwashed by independent specialists

 

[2into1]

As Loz says. Search ‘hovercraft’ mode here for more info.

 

[TripleBee]

The regen seems to work via the satnav, it always kicks in as I pull onto my drive

Try to set your destination a few miles earlier. Maybe your regen will be ready when you are home then?

 

[Loz]

Very close, but it actually fills with soot and then this is burnt off leaving a small amount of ash.
The ash gradually builds up, but once full the filter has to be replaced (dealer) or removed and backwashed by independent specialists

Yes I knew that but, I was trying to keep it short and simple.