Service Issues: XC90 D5 engine DPF (Diesel Particulate Filter)

[volvic40]

Hello Shimon, I must say your explanations of dpf technology are the best I have seen to date
I have spoken to all sorts of dealerships and mechanics, and never get the impression anyone really knows what is happening.

I wonder if you or anyone else, could clarify something for me please? I understand that to perform a routine regeneration, the exhaust has to get hot and this prompts the car to add fuel to the exhaust to assist combustion of the particulates. This is typically described as a 10-15 minute "blast" in a lowish gear to get the revs above 2000 or so. What i want to ask is, what prompts the system to abort the process, and dump diesel into the sump or whatever? Is it the temperature dropping or pressure or revs?

What I am getting at is if you drive along an A road for 20 minutes at 50mph in 4th gear so the revs are around 3000, will that all be negated by negotiating a few roundabouts where you drop down to low speed, stop to give way, and then take off again?

Obviously the temperature will stay pretty constant for those 10 second interludes, but the revs/speed/ will drop.

So would that type of trip be enough to regen the dpf on a regular basis? I do a fair bit of inter-urban driving on A roads but only occasionally go on a motorway trip (every month or so). i am currently weighing up whether to go for petrol or diesel model. The petrol variants are rather rare in the used market but there are loads of diesels around I have received some excellent advice from members and I am just finalising my thoughts

Any advice would be most appreciated.

[RoyMacDonald]

We just drive normally. Haven't had any DPF issues yet on the two Volvos that have them.

[volvic40]

Hi thanks for your reply.

My "normal" driving is a mixture of urban and some inter-urban A roads - but Motorway only every month or so.

Are A roads OK does anyone think, because although you are trundling along at 40/50 and could drop it a gear to get the revs up for a distance, the stop start nature with roundabouts and the like may convince the system to abort the regen process.

I had problems with my dpf on a Mazda 6 over the winter because I did mostly urban for few weeks and the weather was cold I guess. Having said that I had driven it successfully for 6 years with no previous problems....

I just want to understand the process of regen a bit better and Shimon seems to be very clued up!

[RoyMacDonald]

Originally Posted by volvic40

Hi thanks for your reply.

My "normal" driving is a mixture of urban and some inter-urban A roads - but Motorway only every month or so.

Are A roads OK does anyone think, because although you are trundling along at 40/50 and could drop it a gear to get the revs up for a distance, the stop start nature with roundabouts and the like may convince the system to abort the regen process.

I had problems with my dpf on a Mazda 6 over the winter because I did mostly urban for few weeks and the weather was cold I guess. Having said that I had driven it successfully for 6 years with no previous problems....

I just want to understand the process of regen a bit better and Shimon seems to be very clued up!

I'd say mine is 30% B roads 30% A roads 40% motorway overall but it varies as there are no motorways locally so the motorway bit only happens in the summer months normally. I read somewhere the Volvo regeneration happens in the mid 40 mph range on the new models. Which indicates that the rpm doesn't need to be that high for the Euro 5 engines to regenerate.

[volvic40]

Hmm Thanks Roy that's interesting.

Since posting originally we have seen the V40 XC which we liked the look of. I know it's pathetic because the XC bit is only cosmetic, but there you go!

So we may have painted ourselves into a corner because the petrol XC is apparently only available with a formula one engine and finding a pre-loved one is next to impossible.

On the other hand the used diesels are very commonplace and pretty well specced, which makes me think if the whole world is buying D2s and D3s I may be over thinking it!

Thanks for your help anyway, you seem to have quite a collection of Volvos so they must be doing something right!

[RoyMacDonald]

Originally Posted by volvic40

Hmm Thanks Roy that's interesting.

Since posting originally we have seen the V40 XC which we liked the look of. I know it's pathetic because the XC bit is only cosmetic, but there you go!

So we may have painted ourselves into a corner because the petrol XC is apparently only available with a formula one engine and finding a pre-loved one is next to impossible.

On the other hand the used diesels are very commonplace and pretty well specced, which makes me think if the whole world is buying D2s and D3s I may be over thinking it!

Thanks for your help anyway, you seem to have quite a collection of Volvos so they must be doing something right!

I take it you mean the V40 Cross Country? It has a higher ride height and softer long travel suspension. It's more comfortable for passengers from my experience.

[Jim314]

Originally Posted by shimon340

. . . having worked on dpfs ( research dept ) I think I can help out here.

Basically, the diesel particulate filter ( dpf ) is effectively a fine mesh placed in the exhaust. It catches diesel particulates (soot). The filter is also coated with some metals which act as a catalyst to burn the soot. The catalyst lowers the temperature at which the carbon / soot combusts. This therefore removes the soot from the exhaust, lowers the vehicles particulate emissions and therefore allows compliance with Euro 4.
. . .
S

This post of Shimon's and his several following posts are very illuminating.

If you think a regeneration is needed or will be soon, but don't have a high speed run planned soon, and you are in a relatively low speed run, can't you just drive in a lower gear to get the engine rpms up to the needed level? I know this will use more fuel than one would like, but if the alternative is a clogged DPF, then it would seen to be the correct thing to do.

[volvic40]

This is kind of where I came in, the issue being that any non-motorway run will usually entail some stop and start even if it's just a give way at a roundabout on an A road every few miles. The temperature in the exhaust will stay high for that short period but the revs will drop unless you have rally driver pedal technique.

so will that interruption cause the regen to abort or will it just carry on? i.e. is a highish speed run on an A road OK, as opposed to the slow 1st gear crawl to work in a queue on a typical commute/school run which is clearly NBG.

I am still slightly fuzzy about this!!

Anyone?

[volvic40]

Hi sorry Roy yes I do mean the V40 cross country.

It is rather handsome, but only diesel unless you have T4 or T5 I think, which are a little excessive and pricey and nowhere to be found in a used form anyway.

On the other hand the D2/D3 version looks like a good 2nd hand buy after 1-2 years and there seems to be a wide choice.

Bit perplexing!

[RoyMacDonald]

Originally Posted by volvic40

Hi sorry Roy yes I do mean the V40 cross country.

It is rather handsome, but only diesel unless you have T4 or T5 I think, which are a little excessive and pricey and nowhere to be found in a used form anyway.

On the other hand the D2/D3 version looks like a good 2nd hand buy after 1-2 years and there seems to be a wide choice.

Bit perplexing!

Volvo Selekt have plenty of second hand ones of all engine types. The D2 is the most popular probably.

I don't read a 100% of the posts but my observation on the selection I've read is that a few posts have blamed the DPF for what turned out to be an unrelated issue, a few have had sensor problems with the DPF that required the sensors to be changed, a few have been unclear what the problem was with the DPF, but by far the most were from people who objected to the design as they believe it would shorten the life of the engine.

As I commented there are lots of very high mileage Volvo DPF cars around. My friend has owned an XC70 D5 with a DPF for 8 years without any problems and he doesn't like motorways and rarely chooses to use them.