Diesel Particulate Filter

[jggolf]

We only have 1735k on the clock, so does the GT's just go into a regeneration cycle when it feels it needs to, or should I take it to another dealer and get them to check the sensor

Feedback greatly appreciated

Gill

[Russ59]

We only have 1735k on the clock, so does the GT's just go into a regeneration cycle when it feels it needs to, or should I take it to another dealer and get them to check the sensor

Feedback greatly appreciated

Gill

There are quite a few posts on this already so I won't start a new one but AFAIK YES !! it will start a regeneration cycle when it feels it necessary to do so. Having said that though I don't recall seeing a DPF warning light in the dash when mine did it, then again I wasn't really looking as I was a little preoccupied trying to find somewhere to pull over while it was $hitting itself. If the light keeps coming on at regular intervals then you may have to get the dealer to check it.

Russ

[bluey]

Prevention of DPF clogging by reducing smoke:
a. driving out of the "smoke zone".
b. high cetane fuel or add a cetane improving additive (eg Amsoil, Morey's diesel smoke killer, etc)

Otherwise, the AA has a good article on DPFs.

This catalyst manufacturer has some data on DPF regeneration and active regeneration data.

This thread also has some useful info.

[bluey]

Did you mean Golf GT TDI ? The Golf GTI is petrol (as is the Polo GTI).

This week I saw a red Golf V with proper GTI badge on the left and 2.0 TDI on the right. Was that real? Is it a chipped GT and someone has changed badges?? Is it a GTI and someone has done an engine swap?? Is is a foreign import??


PS I am reading about some reliability issues with VAG 2.0 diesels with DPFs to meet Euro Cat IV regulations. Things to be aware of...

[CatonaPC©]

I know my car has a catalytic converter. How does differ from a DPF? Wouldn't there be a potential for soot build up in this?

[Russ59]

Put simply they both do a similar job and that is reduce pollution. The DPF from what I can ascertain is simply newer emissions technology which actually filters fine dust produced by the diesel engine where the CC works to convert the various gases produced and reduce their pollutant effect. I have had to have a CC replaced before on a vehicle due to the build up of crap over time, so yes soot from a diesel will eventually take it's toll on the CC I would think. However from what I have read the DPF is a lot more restrictive as well so it will probably take some time before the soot build up gets the better of a CC. Someone will no doubt come back with a more thorough explanation as this is just my .02 cents worth from a quick online search. It doesn't need to be " Rocket Science " all the time.


Russ

[CatonaPC©]

Thanks Russ. Your explanation was good.

[Greg Roles]

Spot on Russ.

the biggest thing I can see is that whilst a cat is usually a big, fine grid full of straight through channels, the DPF makes the gas cross 90 degrees and is not of a straight through design, hence the restriction.

VW do say in the service bulletins I have that the DPF is a limited life design.
I doubt it's a cheap part!

[Oneofthegreats]

I think the DPF & the Cat. Conv. are a one piece complete unit. Can't remember, but I'll have alook tomorrow if I get a chance.

[Greg Roles]

In the DPF diesels yes they are. Catalyst and filter in one, right after the turbo.

[jggolf]

Well, I took the GT (missy) for a run and revving her over 3200 rpm and holding in 3rd gear at 70k's, which I don't do normally the DPF light went out on the dash.

Thank you every one for your help, I will keep an eye on this. I won't be so worried in the future. It scared the hell out of me then this light came on the dash. The same as when I had an oil light in my old mkV 2.0 tdi came on since then I always carry a 1 ltr of oil is the GT also prone to using a little oil before the first service?

Gill

[Russ59]

Well, I took the GT (missy) for a run and revving her over 3200 rpm and holding in 3rd gear at 70k's, which I don't do normally the DPF light went out on the dash.

Thank you every one for your help, I will keep an eye on this. I won't be so worried in the future. It scared the hell out of me then this light came on the dash. The same as when I had an oil light in my old mkV 2.0 tdi came on since then I always carry a 1 ltr of oil is the GT also prone to using a little oil before the first service?

Gill

I only have around 6000 k's up so far and will be looking at having the 1st service done at 7,500 k's even though VW say 15,000 k intervals. So far I don't think mine has used a drop, although the stupid black dipstick isn't the easiest to read so it may have been slightly over full when I took delivery. I will get around to spraying the dipstick tip in a light colour one day soon so I can see the level properly.


Russ

[Greg Roles]

I've not had to top up yet with 22k's to date. It uses a little between services, but then I'm doing mine every 7500, between dealer visits.

I'd have to say the main form of oil loss is through the vapour, as I drain a hundred ml's or so each 2-3 months from my provent, which the rest of you are ingesting through the inlet.

[bluey]

I understand the DPF is a filter more like a ceramic version of an air filter. (DPF typically has honeycomb structure with alternate ends of pores blocked, so exhaust gas has to pass through walls of ceramic material.) The catalytic convertor has a large surface area but the gases can bump the sides on their way through the holes. (CC typically has a honeycomb of holes - can look through and see light.)

DPFs generate back pressure to start with and can be physically clogged with particles.

CCs don't clog but the precious metal catalysts can be poisoned - no physical backpressure effect but measurable emissions.

[gregozedobe]

VW do say in the service bulletins I have that the DPF is a limited life design.
I doubt it's a cheap part!

AFAIK the DPF fills up because it captures the larger soot particles as you drive.

When flow through the DPF gets too restrictive (ie partially blocked with soot), the ECU "regenerates" (ie runs extra fuel to actually burn the soot). The burnt soot is reduced to a lesser volume of fine ash, which reduces the restriction.

Eventually the DPF gets full of the fine ash and can no longer be effectively regenerated, then it needs to be replaced.

I hope that there are some cheaper aftermarket alternatives when mine needs replacing, as I"m with cogdoc on this one, I can't imagine it will be a cheap fix.