Should I be worried about buying a diesel with dpf?

attila_

I'm looking at getting a new diesel to replace my ageing car. I'm particularly keen on a 330d or saab ttid (2007-2009 years). With the budget I have i'd be looking at one which is around 100k miles which shouldn't be a lot for a diesel.

Now both of these cars as with many diesels have a Diesel Particular Filter (DPF). I have read endless issues with dpf failures and the repairs are very costly (around £1600 for the 330d for example).

The solution for many up to now has been to remove the dpf and program the ECU see here - this is being offered for around £500 plus or minus.

However with the recent government announcement that the DPF will now be checked as part of the MOT I read a lot of forums where people are trying to re-fit their old ones back!

This leaves me with a number of concerns:

• As the regulation comes in Feb 2014 could there be a chance that the second hand car market will be littered with cars that have removed a dpf and not declared it at sale? Especially those who have smashed out the internals of the dpf and left the shell.
  
• If I am going to buy one of the cars mentioned above with 100k miles I'm guessing there's a pretty good chance the dpf is nearing the end of its life. I have heard they are designed for 100-125k miles. Would this be covered under those warranties that garages offer? Me thinks not as its general wear and tear.
  
• Now that the choice of removing a dpf has gone (and I'll be honest I would have done this was it not an MOT failure now) is my only fall back option a replacement with a new DPF costing £1600? Or has anyone got any experience with DPF reconditioning such as this:
  http://www.turnerdiagnostics.com/dpf-cleaning.html

I'm annoyed as I've been looking forward to buying a replacement diesel for a while but I feel like I can't really trust the used car diesel market either because people have removed the dpf or at the mileage I am looking at the dpf is on its way out.



I would welcome people's thoughts on whether I have got anything wrong and what they would do!


I'm leaning towards a petrol but my mileage is too high (20k per annum).

pompeyred

This is an interesting thread because of the warranty issue.


If you are sold a vehicle from a motor trader which has (a) the DPF removed or (b) the dpf develops faults during the warranty period then you might expect to have the fault fixed.


The issue comes where the missing part is recognised, an MOT failure within a warranty because of a missing part might make the trader liable, a fault developing for the same would again raise the same question. The tricky part is proving it was missing at point of sale (how might you credibly state it wasn't you who removed it) and then if you considered a problem (DPF known issues) but didn't ask or check as part of the sales then there is an element of liability on yourself as you would be stating it was a known issue but didn't make relevant enquiries.


The best you can hope for given all conditions is that you buy a vehicle which has the DPF or at the very least a new one or (if by chance) the DPF failed altogether in the warranty period. However I doubt any trader would replace as there are many remedies which might fix the issue, albeit temporarily and at least until the warranty is over.


So, the question really is..... do you need a diesel...? Will you run the engine at high revs for a sustained period on a good run quite frequently, if not, maybe you should consider other engine options.


For clarity I have a diesel, it has a dpf and I bought it thinking I would do high mileage, I don't do as much as I thought, but I do make sure it goes on a good journey and so far so good.

pc1271

I understand the MOT will "check for the presence of" the DPF - not that it is functioning. It might be illegal to drive with a modified DPF, but this wouldn't be picked up at the MOT.








DPFs tend to have trouble on low mileage, short-trip vehicles. If you're looking at something with 100k on the clock and not too old, it's likely to have been used for long motorway runs and have a good DPF.


https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/263018/diesel-particulate-filters-guidance.pdf

harveybobbles

for the sake of 20,000 miles I'd stick to petrol to be honest.

Diesels really aint worth having unless you're doing about 50,000 mls and someone else is paying!

Netwizard

harveybobbles wrote: »

for the sake of 20,000 miles I'd stick to petrol to be honest.

I agree. You will spend more in petrol costs but save when it comes to repairs and you have no expensive DPF's, EGRs etc to worry about.

Unleaded fuel is also cheaper than diesel, so its not all bad. Cruising down the motorway, you can get good economy out of petrols too nowadays.

attila_

I know its not a lot but you would also be saving on car tax if i went for diesel. Take the 330i, same engine size has around £200 per year difference.

I always thought 12-15k was the cut off for diesels..seems to be getting more to get a payback?

I'm surprised no diesel fans on her yet!

Din85

A 330ds dpf should do 140/150,000 miles before needing replacement.

Thats about average for police cars etc when I worked at bmw.

That said I reckon bmws dpfs are some of the most problem free out there, dont see issues with mercedes ones either, vag stuff I saw a lot of issues.

attila_

Din85 wrote: »

A 330ds dpf should do 140/150,000 miles before needing replacement.

Thats about average for police cars etc when I worked at bmw.

That said I reckon bmws dpfs are some of the most problem free out there, dont see issues with mercedes ones either, vag stuff I saw a lot of issues.

Yes that's the feeling I get on forums. It looks like mazdad have serious issues, then vag.

Anyone got experience of cleaning dpf?

Netwizard

attila_ wrote: »

I know its not a lot but you would also be saving on car tax if i went for diesel. Take the 330i, same engine size has around £200 per year difference.

I always thought

Ignore road tax cost. Its a very small cost in the grand scheme of owning a car. The amount of people I see spending £6k on a small runaround because "its only £30 a year to tax" is amazing.

The tax saving on a diesel could be wiped out on one repair

bigjl

attila_ wrote: »

Yes that's the feeling I get on forums. It looks like mazdad have serious issues, then vag.

Anyone got experience of cleaning dpf?

There is a company called Ceramex that clean dpfs. Not with fluid or chemicals which damage them. But with heat in a special oven.

They have been doing bus and LGV dpfs for years.

They also have a way of examining them so you know it is clean with a certificate to prove.

Dpfs will gradually clog due to the ash that builds up during regen. When the soot is burnt off ash is left behind.

Another company in London called DPF Genie use similar technology.

With proper cleaning a dpf will last the life of the car.

And no matter what anybodt says they always get a build up of ash.

Paperbird

Ignore the 12/15/40000 mile break even point because that's based on buying a new car and selling it after three years.
It's not the amount of miles you do but the type of driving that starts the DPF problems, it needs regular 20 to 30 mile runs at 2000rpm or more to keep the DPF clear.
Any main dealer will be able to plug their computer in and tell you if the DPF has been removed.