Diesel intermittent smoke

[neilkf]

Hi all from a newbie.

I've had my Cayenne Diesel since January and three times I have noticed a humungous cloud of blue smoke behind me for a couple of minutes. Performance isn't affected and it's immediately back to normal (for me anyhow - can't speak for the huge pile-up of blinded drivers I've left behind me)

Porsche's answer is this: There is a chamber in the exhaust that collects impurities in order to keep the official emmissions figure as low as poss. This chamber occasionally empties itself into the exhaust where all the last few week's 'impurities' burn themselves off - in my huge clouds of smoke!!!

That would seem to be a feisible explaination but hardly in the spirit of environmental care - save up your pollution and dump it all at once!!

What do you guys think?

Many thanks

Neil Foreman

[cruiser647]

Hi!

Many of the 'ultra-clean' and modern diesels have DPF's (dust particulate filters). And they do exactly as your matey says they do. However, I've never known them to be that bad!

What sort of driving do you do? Lots of small trips? or long trips? And how often does it happen?

[rottenbend]

It does sound like the DPF but on the other hand the Cayenne Diesel uses the same engine as my A6. I would expect that the DPF is exactly the same as well. I've never seen any smoke from the back of car, even when accelerating hard. Driven behind it a few times as well and never seen any smoke.

IIRC the DFP burns off under certain conditions - cruising on the motorway for example.