Engine: D5: Soot Filter driving me crazy...HELP !

[chunderground]

since rang shell and found that v_power does in fact contain bio diesel its the law apparently.

Oh well will just have to change the oil reguarly what a pain.

[chunderground]

if manufacturers do not fix this problem I think there will be a mass market for disabling DPFs. I would far prefer it if motor manufacturers found a fix but 3- 5 years on there is no fix in sight. I would think that the cost of running back to the manufacturers dealer for new DPFs / engines / turbos (the two latter items lubricated with what is effectively vegetable oil) every few thousand miles would be unacceptably expensive to the majority of owners.
Volvo claim it is the bio diesel (vegetable oil) component which is getting into the sump which will not evaporate out.
With the expensive 0w-30 oil volvo spec for the engine it is laughable that they refuse to change the oil when it has been diluted with vegetable oil.
It is now a legal requirement that all diesel fuel has to contain 7% bio fuel.
The DPF engines were designed before this was a legal requirement.
The excess fuel getting into the sump was supposed to evaporate before causing problem. Bio fuel (vegetable oil) does not evaporate. Which is why we now are having this problem.
So the EU created the problem by insisting on DPFs being fitted to diesel engines and the UK government completed the stitch up by insisting on a 7% bio fuel component.
We have been stitched up good and proper the EU and UK legislators and the motor manufacturers.
End of Rant

[Farway]

I worked for the company (johnson matthey) that coated the bare substrates to produce your catalytic (petrol) soot (diesel) filter you use in your volvo. The soot filter is unlike the catalytic converter in the sence you can see thru your catalytic filter with numerious chambers of max 0.7m2 but not the soot filter. The soot filter forces the burnt carbon thru the actual filter (you cannot see thru it) and retain the carbon/gunk and releases the remaining gasses. The soot filter is reliant on a flash of heat to burn off the exess carbon (or regenerated if you wish) and clean the filter out. This will happen however many times during a certain time period but is relaint on reading pressure build up combined with heat to clear and re-start the procedure. On cold starts you produce an emence amount of soot and that is the big problem combined with the short journeys and you can see where we are going with this??
Solution: As someone has mentioned, you have to give the thing a good blast from time to time to generate the heat and clear the filter. If you persistantly keep blocking the filter, the thing WILL STOP WORKING and you WILL HAVE TO REPLACE IT. In theory the system works a charm, in practice , it's crap and costly. It could and possibly might be an option to remove the thing and replace it with a straight thru section which will have to be replaced on every MOT but might work out a dam-side cheaper (Please note the "might work" section...)

[chunderground]

I think removal involves a remap and significant alteration. Swapping back and forth at MOT time is not going to be an option.
The MOT though does not differentiate between DPF diesels and older diesels. The measurements are the same so that may not be a problem. As for the legality of removal is concerned I have no idea. Not an issue for me yet as I have over 2 years warranty to go.
I still think there will be aftermarket conversions available in the future. This technology is not sound.
When manufacturers design the next generation diesel engines it will be sorted. My suspicion is that early DPFs will probably always be a bit of a compromise where frequent oil changes and forced regeneration are required.
But I hope to be proved wrong by others on this forum.
My average speed has been 23mpg and average fuel consumption 23.5 mpg.
It would be interesting to hear these figures from owners who have no problems at all.

[Farway]

23.5 mpg for a diesel!!! My petrol 2.4 gives me 27.8 combined..... Thats fairly heavy going but I suppose with the AWD and a sizeable body

[RoyMacDonald]

My D5 gives 40.1 mpg combined but I don't have the soot filter. I think chunderground has a new engine so it's still tight I would guess. A D5 needs about 50,000 miles to loosen up properly.

[chunderground]

Yes I think the DPF uses more fuel pushing the exhaust gases through that filter. Also it then goes into a regeneration cycle to clear the filter of soot which again uses a lot of fuel.
I have accepted the higher than expected running costs (including more frequent oil changes) cos I just love it and still want to keep it long term.
I recently swapped to a low soot fuel and fuel ave on readout has increased to 25 mpg on display since that reset ( only 250 miles ago )

[adb007]

It seems from some earlier posts that there are still some misunderstandings about the DPF regeneration process.

All diesels produce soot at a rate corresponding to the rate at which they burn fuel. This happens whether you are storming down the motorway or tootling around town. Faulty and cold engines can produce soot at a higher rate. This soot builds up in the DPF (when fitted) which is a soot box and gradually starts to block it.

When the engine senses this, which is about once every tank full of fuel or 400 miles, it starts the 'regeneration' process which pumps neat diesel into the soot box (via the exhaust stroke) to create a small fire there to burn the soot off. This might take 5-10 minutes or so and is not normally noticeable although if you are driving at a steady speed on the flat you might notice the instant fuel consumption reading drop down.

If you park or hit traffic congestion before the burn off process is completed it stops and restarts later once the engine is hot again. This means you could have just completed a long fast run but still left the regeneration process in limbo. More soot accumulates while the engine is next coming up to temperature.

If your normal driving pattern is long and fast runs the failed regeneration will probably complete later next time without problem. If you only go for shortish runs after the suspended/failed regeneration, soot continues to build up until, at about 80% capacity of the soot box (DPF), you get visual warnings.

If you do not then soon take the car for a longish run (20 minutes after engine gets hot) at high revs (2500-3500) then soot will not be completely burnt off and so the engine will trigger the next regeneration cycle earlier than expected. This cycle of operation near the edge of regeneration can go on and on with short distance driving patterns.

If you do NOT take the car for a high rev run (drop to a low gear or use 'L' if automatic to keep speed down), when the soot box is about 90% full, the engine will go into limp home mode and you are in for a service visit.

You can see from the above that long high speed runs when the regeneration process has not yet been kicked off by the engine management software doesn't help avoid the problem. they are only needed when the regeneration has started.

If you are wondering about overall fuel economy when you have to blast around to clear the DPF of soot when you bought a diesel to get good economy, well, you are not alone! It is not just Volvo who have the problem.

On a separate issue, the recent Volvo recall for software update applied to my V70 2008 D5 185 Geartronic seems to have fixed the rising oil level problem for me. Previously the oil level went up 20+ mm on the dipstick in less that 2000 miles but has since remained steady after 1600 further miles post software update.

Now waiting to see whether the DPF regeneration still works properly when using less fuel for the regeneration to avoid it going into the sump.

[Dynosaur]

What WOULD have been useful in the SW update would have been a message to show an aborted regen cycle, together with a tally for previous abortions.
Then at least the user knows exactly how urgent the situation is.
How difficult can that be ?
Or is it actually perfectly simple but substantially less profitable than a dealership regen costing £$hedloads ?

[adb007]

Hi Dynosaur

I agree with you absolutely about the software possibly flagging up the warning of failed DPF regens. Brilliant idea! Can't believe it can't be done given all the other 'messages' that can appear on the display and the ability of the system to store other fault codes.

I think it should be suggested to them.

Not sure about the conspiracy theory though (sending owners to dealers for profitable emergency regens) as its a pain for the dealers (it disrupts their schedules) and the PR ain't good either!