Engine Fan stays on when car stops.

[Audi head]

Hi guys just a question,is it normal for the engine fan to stay on after a good spin in the car,it stays on for 5 mins or so.Ive only noticed it lately,maybe it's normal after a fast run but thought I'd ask anyways just incase..

[Guest 2]

you've interrupted a dpf regen, fan will stay on for a few mins. totally normal.

[johnsimcox]

you've interrupted a dpf regen, fan will stay on for a few mins. totally normal.

Chris, Perhaps this should become a sticky! Seems to be a question that comes along every couple of months

[Hellodave.]

The fan stays running on petrol cars too (well, the RS6 I drove anyway). No DPF so presumably it's just to help cool everything down after a hard run.

[Omegadirective]

I can second the fact it's DPF. I took mine in when I was passing just to confirm it was dpf. Tech had it on the diags just to confirm and yeah, just the DPF. Mine was staying on after every run but it's now settled down.

[Furillo]

Don't forget that lovely burning smell

[MarkTM]

The fan stays running on petrol cars too (well, the RS6 I drove anyway). No DPF so presumably it's just to help cool everything down after a hard run.

Does on my old petrol/LPG Jaguar too.

[danh89]

I'm 600 miles in on my bitdi and when i got out of it last night the fans stayed on and there was a burning smell, was going to take it to Audi but I presume this is completely normal?

Dan

[johnsimcox]

I'm 600 miles in on my bitdi and when i got out of it last night the fans stayed on and there was a burning smell, was going to take it to Audi but I presume this is completely normal?

Dan


yes!

[Whippy53]

Chris, Perhaps this should become a sticky! Seems to be a question that comes along every couple of months

Or, or people could simply read the owners manual. Or even bother to read some of the threads?

[Furillo]

Could be worse. I had an old Mark 1 Capri 3000GT. Engine stayed on when switched off:)

[john2107]

Hi, can someone more knowledgeable than me please explain what makes this DPF regen cycle kick in. My commute is 120 miles, taking just over an hour, over half of which is motorway. Yet very often, when I arrive home in the the evening, the fans stay on and a regen cycle is happening. I can now recognise this over the last few (non Mway) miles as the engine seems a little more noisy and just seems a little more lively. I would have thought my driving circumstances are virtually ideal for keeping the engine and exhaust system in good nick.

I do almost zero miles in traffic, so how come the cycle kicks in so much? Even after a fairly spirited drive, it will happen sometimes.

Any thoughts welcome...

Cheers
J

[Bloater]

I always though that the fan stayed on to keep blowing cooler air through the radiator and drawing air from the ground around the engine bay to dissipate the heat more, to prevent a heat soak on the engine and all that. I know when I had to have a manual dpf regen performed on my A4 by the roadside man, the engine has to be running and the exhaust red hot, very lean fuel mixture. Quite how that is supposed to happen with just the fan running is beyond me.

Obviously some are cleverer than me, so maybe I am wrong in my assumption on the fan issue.

[fest0r]

Hi, can someone more knowledgeable than me please explain what makes this DPF regen cycle kick in. My commute is 120 miles, taking just over an hour, over half of which is motorway. Yet very often, when I arrive home in the the evening, the fans stay on and a regen cycle is happening. I can now recognise this over the last few (non Mway) miles as the engine seems a little more noisy and just seems a little more lively. I would have thought my driving circumstances are virtually ideal for keeping the engine and exhaust system in good nick.

I do almost zero miles in traffic, so how come the cycle kicks in so much? Even after a fairly spirited drive, it will happen sometimes.

Any thoughts welcome...

Cheers
J

Might be the auto/low revs keeping the temp down in this weather. Knock it into manual and run it a 3.5/4k revs for 20min. It may just keep doing it if the regen keeps getting interrupted.

[jcdub]

Regeneration happens when the engine is running at full operating temperature and the revs are running between 1850 and 2250 rpm. If ash / carbon volumes in the dpf reach a certain level, regeneration will activate. If like yourself, your mainly doing motorway miles it will then activate on a time / mileage basis. That's why you'd still get regenerations regardless of motorway miles.

[fest0r]

Regeneration happens when the engine is running at full operating temperature and the revs are running between 1850 and 2250 rpm. If ash / carbon volumes in the dpf reach a certain level, regeneration will activate. If like yourself, your mainly doing motorway miles it will then activate on a time / mileage basis. That's why you'd still get regenerations regardless of motorway miles.

Loads of cold air on the motorway might be keeping the temps too low for the regen to kick in until it’s pulling into the driveway. Instead of waiting for an automated system regen you should be able to clear all the build up by doubling those revs for 15/20 min… right?

[Whippy53]

Try doing your normal journey with the box in s mode.

[jcdub]

Not necessarily. During a regen extra fuel is dumped in to the dpf in order to raise the temperature which in turn caused the ash / carbon to burn off the ceramic filter. It would take extreme cold temperature to do the dpf getting up to a regeneration temperature.

[jcdub]

You can read this post on the seat forum that will explain all ��
DPF Info - All CR-TDI Owners Should Read This - SEAT Cupra.net - SEAT Forum (http://www.seatcupra.net/forums/showthread.php?t=263734)

[Whippy53]

During an active regen that's true, I was referring to a passive regen.

[M1tchy]

Very good info and an interesting read. Cheers


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[Guest 2]

DPF info (http://www.vwaudiforum.co.uk/forum/showthread.php?141943-DPF-info&highlight=dpf+info)

On here too :)

[jcdub]

I've noticed a drop in performance during a regent, also the idle is slightly high than normal if sitting at idle.
Is just unfortunate timing if an engine Is regenerating as your coming to an end of your journey. At times I have taken it on the road again for a shot trip in order to let it complete it's cycle;)

[jcdub]

Thanks Chris!


DPF info (http://www.vwaudiforum.co.uk/forum/showthread.php?141943-DPF-info&highlight=dpf+info)

On here too :)