MKV DPF dissection

[Greg Roles]

Finally started cutting up Ryans old clogged DPF today. VERY interesting..

First is the very fibrous and weak insulative layer around the inside of the can, you can see it in the flap I cut off. As it's no doubt something along the lines of asbestos, I'm wary of breathing it in! Secondly the innards of the DPF were a LOT cleaner than I thought. Seems the filter is made of full length cels that alternate at the very end being closed, and whilst the actual top was quite sooty, it was mainly full of the white ash you can see. This must be what builds up and can;t be burnt back off. I actually got very little black on my hands which suprised me, but a ton of ash came out of it. Perhaps Ryan (ryder01) I got it off had it backflushed and baked or something, but I expected a lot more soot. The cermaic was incredibly strong, and laying into it with a hammer had little effect, had to break it up with a big screwdriver and the hammer. Very much like ceramic, made the same sound as it broke up, and cracked the same. Once I got a central section out, I was able to remove big chunks of the core which I will keep for future study.

In all the medium was far more symmetrical and uniform that I was expecting, and the ash that fills it was a suprise being white.

[Greg Roles]

And the detail,

[Greg Roles]

Note the ash and symmetry in the design. Seems the filter is made up of several chambers which are ceramically bonded together probably to give it extra strength against cracking.

[Greg Roles]

Here's the big chunks showing the inner layout.

[Transporter]

Some good work there, Greg. I see the box is ready to be welded up, or not?

[kaanage]

Note the ash and symmetry in the design. Seems the filter is made up of several chambers which are ceramically bonded together probably to give it extra strength against cracking.

I'd say the "chambers" are standard base units used to construct the DPFs for varying sizes. It makes sense that the ash is white since the regen cycles should burn off the carbon. The poor thing much have been regenerating quite a lot near the end in a futile effort to clear the obstruction hence the relative lack of soot.

So there's no separate cat section at all?

[Greg Roles]

Some good work there, Greg. I see the box is ready to be welded up, or not?

Not by a long shot.....

I'd say the "chambers" are standard base units used to construct the DPFs for varying sizes. It makes sense that the ash is white since the regen cycles should burn off the carbon. The poor thing much have been regenerating quite a lot near the end in a futile effort to clear the obstruction hence the relative lack of soot.

So there's no separate cat section at all?

Nope, it all looked uniform, seems there must be some platinum in the front portion of the DPF, and less towards the back, but there was neither any silver, nor obvious sign of difference front to back, it must be integrated in the walls.

The new MK6 DPF has very obvious seperate pieces, but so too this is to keep the costs of replacing the DPF down, and makes for even lower emissions.

From the rear of the engine....

[noone]

JohnW provided a link to some VW tech manuals, this was in there...

http://www.volkspage.net/technik/ssp/ssp/SSP_336.pdf

Nice info Greg

[poyta]

No wonder you gain so much by removing it - it looks very restrictive.

[kaanage]

JohnW provided a link to some VW tech manuals, this was in there...

http://www.volkspage.net/technik/ssp/ssp/SSP_336.pdf

That's excellent - it clearly shows all the elements unique to the MkV GT diesel engine (at a basic level).
But the fact that VW moved away from the catalyst coated particulate filter so quickly shows the drawbacks of this since the DPFs must be clogging faster than their intended lifespan.