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DIESELS AND PARTICULATE FILTERS
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I've been told by everyone to whom I've mentioned buying a diesel that DPFs are a nightmare. This is something I wasn't overly aware of due to my hitherto almost total disinterest in the dirty fuel. Apparently they need to be driven at 2000rpm+ for 45 minutes regularly to allow it to regenerate and while doing so it feels like its losing power and misfiring.

2000rpm in an auto 330d is something over 80mph in top, so realistically you'll need to hold it in a lower gear to avoid driving miles just to get it to regenerate. Is this really as big an issue as people are making out? Quite tempted to say sod it and go for an S4 Avant instead.

Unless you are doing ~18k or more get the 330i. That's a lovely engine.

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Cheers,
Mike

I'm sure the odd bit of motorway driving and they'll be fine.

Go on, go for the S4 Avant, as I'd like to have a ride in one.

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Just give it a good beasting every once in a while, seems to work on mine (assuming it has a DPF..) I just do it to keep the VVT clean :lol:

I have had plenty of modern high mileage diesels and it has never been a problem.

Worst case situation is you have to force a regeneration cycle or spend £300 on getting the DPF washed/removed+reprogrammed.

I asked the chap at Darren Wood specialists in Stockport about whether the 330D was worth going for as I couldn't find many 330i's in the spec I wanted.

He reeled off a number of acronyms with regard to the 330D, of which the DPF was one, and implied they saw these things regularly. It came down to the emerging rule of: if you aren't doing about 15-18k or more then get the petrol as it's pretty bullet-proof.

Obviously that wasn't factoring in the issues that the later ED petrol models have with fuel pumps and injectors.

There's a lot of hysteria re. DPFs. It's usually spouted by people that own previous versions of similar derv engines that don't have a DPF.

That said, if you're only doing short runs then, in theory, you might get problems.

Apparently in the D5 V70 you need to get the exhaust temp up for about 20mins.
It then squirts fuel at the filter to burn up the soot. This needs doing every few hundred miles. If you don't, then you get a message on the dash telling you it needs to regenerate so go for a longer drive.

Ours gets mostly used for short runs. I've not seen the message once in the 8k miles since we've been driving it.
It does seem to run better and give slightly better mpg after a trip down the motorway though.
I think the major drawback is increased fuel consumption. But at least they don't smoke like an old fashioned derv.

Ran a 525D M sport auto for 85k in two years and a 530d M sport for another 80k the two years after, also a C320 CDI for nearly 60k. Had no problems at all.

Jobbo said...

I've been told by everyone to whom I've mentioned buying a diesel that DPFs are a nightmare. This is something I wasn't overly aware of due to my hitherto almost total disinterest in the dirty fuel. Apparently they need to be driven at 2000rpm+ for 45 minutes regularly to allow it to regenerate and while doing so it feels like its losing power and misfiring.

2000rpm in an auto 330d is something over 80mph in top, so realistically you'll need to hold it in a lower gear to avoid driving miles just to get it to regenerate. Is this really as big an issue as people are making out? Quite tempted to say sod it and go for an S4 Avant instead.

I got the old man to give his car big revs when he starts it. Drives it like Ms Daisy around town/short runs and it shuts the turbo down on his X Type 2.0 diesel now and again. Main stealer wanted to replace the turbo for £1500 the last time. Local mechanic stripped it down & cleaned it for £120. Said it needs a run to get up to temp to burn off the particles as they try to re-burn a much as possible for efficiency. Or something like that...

RJW said...

Ran a 525D M sport auto for 85k in two years and a 530d M sport for another 80k the two years after, also a C320 CDI for nearly 60k. Had no problems at all.

Sounds like they're getting the right kind of use though.

Updated December 21, 2012 at 11:20 AM

My parents X5 was used purely as a school runabout in my last year at school where it did a 8 mile trip twice a day and nothing happened to it, it's now (past 2 years) been delegated to my dads 4 mile commute to central London and back everyday plus taking the dogs to Hyde Park and it's fine. It maybe sees a motorway 5 times a year. There does seem to be a lot of internet forum rubbish about these things clogging up.
When they do get dirty they regen themselves which takes like 10 minutes and you can hear it go a bit rougher and vibrate more, then it's fine for a few months till that happens again.

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Making pancake mix for your mums pancake tits.

It was actually a Volvo dealer who told us not to buy a diesel XC90 when we tried to buy one! And no he didn't just happen to have a handy petrol one to sell us.

He said his wife's diesel Volvo "needed a new engine" within 10k miles because it was only used for short journeys and it seriously overclogged its DPF.

No idea why a clogged DPF would kill the engine, but he had no reason to say that if it didn't happen, in fact quite the reverse.

Maybe Volvo DPFs are DIW?

ETA I think he said his wife ignored the DPF warning light... :roll:

Updated December 21, 2012 at 11:50 AM

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Swervin_Mervin said...

It came down to the emerging rule of: if you aren't doing about 15-18k or more then get the petrol as it's pretty bullet-proof.

Yep, I'm still of the opinion that you need to do more than 15k a year, for a diesel to be just about a viable alternative to a petrol.

I think the main issue was with 1st gen dpf's.

The later ones are supposed to be fine as long as you are not driving short distances all the time. Italian tune up is always recommended every so often to clear it out even on the non dpf diesels.

Diesel Taxi said...

I think the main issue was with 1st gen dpf's.

The later ones are supposed to be fine as long as you are not driving short distances all the time. Italian tune up is always recommended every so often to clear it out even on the non dpf diesels.


That's the exact problem, a lot of diesel SUVs are used for the school runs only and maybe one family holiday per year. That's what can kill a DPF, although I don't really know how disastrous that is.

But I'm glad people are of the opinion now that diesels are only worth buying if doing over 18k miles a year. Until very recently I thought that diesels were perceived to be the default choice for virtually every car bar small hatches.

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They are cheaper as company cars though. And if the childminder-run diesel SUV breaks 'cos of a DPF it'll be fixed. As long as you did what it said in the manual or acted on an on dash warning.

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Funnily enought, I was talking to a tuna about DPF's on the 159 2.4 diesels.

If you do alot of motorway miles, its fine. Otherwise, remove it - people report it feeling more spritely without it too.

Not sure how removing it places you in terms of emissions?

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ClubLupo
Technomotive - Games, Cars, Stuff

I won't be doing short trips, but I'll be doing ~20 mile trips into Birmingham which means slow, traffic, etc which I think means I am unlikely to get the DPF to regenerate in normal use.

Other thing I've been wondering is which would give better mpg (or suffer least drop-off) when sitting in traffic, a petrol or diesel?

As for going for a 330i; not sure why I'd go for that over the 335i or S4, but to be honest the choice is probably down to keeping the 545 or buying an S4 now. No reason to swap the 5 for a 3.

Jobbo said...

I won't be doing short trips, but I'll be doing ~20 mile trips into Birmingham which means slow, traffic, etc which I think means I am unlikely to get the DPF to regenerate in normal use.

Other thing I've been wondering is which would give better mpg (or suffer least drop-off) when sitting in traffic, a petrol or diesel?

As for going for a 330i; not sure why I'd go for that over the 335i or S4, but to be honest the choice is probably down to keeping the 545 or buying an S4 now. No reason to swap the 5 for a 3.

Keep the 545i then.

Diesels are more efficient at the fiddly stop-start part throttle stuff. Only when you get towards full load situations that the two converge.

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Cheers,
Mike

The other point re school runs is, diesels take longer to warm up to their efficient operating temperature and as I've said before, another family who have the XC90 D5 only get 22mpg when using it on the school runs, whereas we get 18/19, so not much in it. Especially when you take the cost difference between petrol and diesel at the pumps and indeed usually when buying the car.

Finally of course in the XC90's case it is infinitely preferable to have a 4.4 Yammie V8 to listen to and have its 315hp to haul the XC90's 2 tonnes along with, rather than the wheezy 2.5TDI and its piddling 195hp and dangerously slow 0-60 time... ;)

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