Tiguan TDI - how often does it need a decent run?

[mojo]

Hi guys,

I've already posted this question in the introductions section, but thought I'd put it in the diesel area as well.

We are looking at buying a Tiguan, and are considering the TDI over the TSI. Most of the driving through the week will be short (10 - 20 minute) city trips, to and from work each day. I realise that this sort of driving is not going to be great for the TDI - so how often, and for how long, does it need a decent run? If we are taking it for a hour's run on the freeway each weekend, would that keep it happy?

[team_v]

The main problem would be with the DPF clogging due to the short trips and city driving = lack of high revs/exhaust temps.

I am not sure how the DPF regeneration works so hopefully someone can clarify whether a weekly trip on the freeway would clear the DPF.

All i know is that it's an expensive feature to replace when it gets filled/clogged

[Russ59]

I have had my '08 GT TDI (with DPF) for around 2 years now and I have noticed that short trips around town does seem to make it regenerate more frequently. I also feel that it will be made worse if the car doesn't get to full operating temperature due to the short trips as I understand it, it relies on heat to burn the crap from the DPF. I moved house recently and I'm now about 30+ minutes from the nearest main town and I find the car is definitely running better due to longer runs. I really love the diesel power and economy and am still more than happy with my choice of engine and giving it a bit of a fang quite often to keep the DPF happy is not a problem for me

[Arctra]

There is a pretty good explanation on DPF regeneration on Wikipedia here: Diesel particulate filter - Wikipedia, the free encyclopedia

Basically, the filter catches the soot that would ordinarily be expelled from the exhaust as a puff of black smoke - a classic old deisel characteristic that you should not really see on those fitted with a DPF now. The soot gathers on the catalyst covered filter, and in order for it to be cleaned, the filter has to get to a temp that makes the soot just fall off. So the trick isn't really about how long a "clearing drive" you go for - it's more about getting the DPF cat up to a nice temp to clean itself. Best way to do that is slip it into tiptronic and manually ensure the engine stays above 2000rpm for a few minutes. That way the turbo is boosting and everything gets nice and hot.

As for knowing when you need to do this, there are 2 early indicators really. The first I have noticed is a change in the sound of the engine/exhaust when things are getting clogged. It sounds deeper with more resonance. Failing that, you will notice the engine idling noticeably faster when pulled up at traffic lights and things. My engine normally idles with a fuel usage of aroun 0.7 L/hr on the MFD without the aircon on, and 0.9 to 1 L/Hr with the aircon on. When the DPF need cleaning, it will idle at over 1.3 L/Hr. First time it happen I worried a little, but after planting my foot a few times pulling away from the lights, it cleared itself and went back to a normal idle.

Basically make sure that at least once or twice in every 10 drives you give it a good solid workout and you should be fine. Hope that helps.

[Transporter]

If, you drive just "NORMALLY" in the city and then you go once a week for a long run on freeway you should be "OK". Our Touareg runs mainly in the city and we have no problems with it. The Tiguan will be mainly city car and I have no plans to take it to freeway on regular basis just to burn the sooth from the DPF. The DPF's technology is improving all the time. For example a new temp. sensors for DPF boxes from Denso and others are longer and they read the temperatures more accurately now, so there should be less stories that you read on the net about the DPF problems, mostly related to sensors failure that caused the DPF blockage.

[mojo]

Thanks for the info guys. We'll make our decision soon and hopefully order one in the next week or so!