hi all,my cooling fan ran on for about 5mins after i parked up tonight,engine temp was on the normal position as it should be,any idea why it would do this???.

mike.

hi all,my cooling fan ran on for about 5mins after i parked up tonight,engine temp was on the normal position as it should be,any idea why it would do this???.

mike.

I think there was a previous post on this. It may be something to do with the oil cooling as well as the water.

Hi,

believe you have just experienced a DPF regen, mines done it twice although not for some time now.

Regards,

TP

Found an earlier post and, as TP says, the extra cooling was as the result of a DPF regen. Again I had this happen to me twice within two months of owning the car but not since. (I do mostly open road driving and don't have to tootle around town)

I think it was the electronic "brain"!?! flexing its programs and making sure that DPF regen was working.

Edited 26 August, 201015 yr by Terfyn

Little coincidence. Happened to me a couple of days ago. Temperature appeared normal, and had not been pushing it at all. Mileage just over 2500. I can stop worrying about that then. Thank you gentlemen.

There is also the fact that once you stop the engine actually gets hotter, because it looses the ram effect of the air passing through the rad as you move.

Happened to me last night as well when I got home after a 20 mile motorway run.

Never noticed it before.

Fan was very noticeable and the engine compartment very hot.

Fan must have carried on for good 5-10 mins.

Everything seems fine since.

This is normal peration. The engine was in the middle of a DPF regeneration when you stopped. The regeneration of the DPF also generates a little NOx, so if you sniff the tailpipe, you will notice a distinktly different smeall, as the NOx has an acrid odour. If you had a stop with the engine running, you might also have noticed that the idle was 200 rpm higher at around 1000 rpm instead of the usual 800.

Nothing t be worried about.

Aaah. I had noticed that the maxidot was asking me to select a lower gear ( ie 4th when I would normally be in 5th, and 3rd instead of 4th ) as I approached home. The higher idling speed may have been responsible for this. I have to say that I did not notice the increased idle though. Everything has been "normal" since.

This is normal peration. The engine was in the middle of a DPF regeneration when you stopped. The regeneration of the DPF also generates a little NOx, so if you sniff the tailpipe, you will notice a distinktly different smeall, as the NOx has an acrid odour. If you had a stop with the engine running, you might also have noticed that the idle was 200 rpm higher at around 1000 rpm instead of the usual 800.

Nothing t be worried about.

Thanks Agerbundsen, that's fascinating. I'll check that next time.

I realise it depends on driving conditions but roughtly how often is regeneration needed and how does it know?

Thanks Agerbundsen, that's fascinating. I'll check that next time.

I realise it depends on driving conditions but roughtly how often is regeneration needed and how does it know?

How often depends on your driving.

If it needs cleaning while you are on the motorway, you will not notice it, unless your eyes are glued to the instant fuel consumption display on the MFD - and you are not, are you?

There is a measurement of differential pressure across the catalyst (DPF) somewhere, and when the pressure drop gets too high, it regenerates, basically by increasing the exhaust temperature. At the higher temperature, the catalyst causes the soot to burn into gaseous components, which them mostly oxidize to CO2 and water, but also a little NOx (NO2 and NO3) and maybe a little SO2 as well.