I just wonder if you can provide a simple conclusion of what you think should be done
a) If the dpf is not like mine, is close coupled to the engine, or if it has 2 pressure pipes, then none of what I have done applies to those systems. Once you know you have one of these dpf | Flickr - Photo Sharing!
, located beneath the gear stick, then you can consider drilling as a solution.
b) establish if you even have a choked dpf first using a pressure test, either with a laptop and diagnostic software to read the dpf pressure (labelled as the differential pressure sensor in diagnostics) , OR, by removing the temperature sensor and simply observing the force of the escaping exhaust gas when the engine is revved to 2500rpm. If it sounds a bit like a burst airline, or you can't stop it coming out with just a little bit of thumb pressure, then it's blocked.
Avoid breathing the exhaust gas of course. A manual pressure gauge can be connected to the temperature sensor hole. If you had over 70mbar of pressure at 2000rpm then drilling at least some of the core out wouldn't be a waste of your time. Obviously there isn't much data about when the pressure is considered to be too high, yet.
c) drill into the rear section of the dpf, through the exit pipe. Stop drilling before or when you reach the position of the temperature sensor mounting (take sensor out first of all) Do not drill into the front section catalyst on the other side of the temperature sensor position, that section is a diesel oxidation catalyst which helps to keep emmissions down.
If you're nervous just try one hole, you can go back for more. If you don't want to drill all the way through the dpf core straight away, then I found that just drilling part way into the rear of the filter structure made a vast difference. ( a shorter drill might still be effective there)
I drilled mine in situ, removing it might make life easier.
This video points to the only two bolts I needed to undo to get access to the rear of the dpf http://www.youtube.com/watch?v=3KS-9...1&feature=plcp
If your dpf is as badly blocked as mine, then even just 2 or 3 holes all the way through, or a few long random holes up the middle and sides which stop short of the temperature sensor position will make a big difference.
Pulling the exhaust off the dpf exit pipe might be tricky if it's old, but once it comes off it goes back easily. (I take no blame for damaged exhausts that were already about to fall off
You don't need the exhaust to be on to check the pressure so you could easily drill a little, check pressure, drill some more, check pressure again...
Then change the oil
It's helpful, but not essential, if you perform a 'replace particulate filter' routine using the diagnostic software. (Maybe a garage can do it for a small fee, it takes only 10 seconds)
If you want to take pictures of your dpf and post them, to confirm , or to get an opinion either before or after, feel free to do that.
I also think that washing this type of dpf is a workable solution too. You would need to remove it to do a good job. A bit of a soak in a water bath wouldn't harm it first and that would give compacted soot time to loosen up. Pass plenty of water from both ends, but I think you should always finish off by pouring a lot of water down the front entrance pipe, to wash contaminants off the catalyst at the front. (but it can cope with some soot contamination by the looks of it).
I don't know how long the washing would give yoiu relief for though. If the driving habits are what caused the blockage it would probably become sooted up again, but you could clear error codes for a reasonable period at least. (educated guess)