Dpf arguments

[Borys]

Heard and read lots of dpf debates
I just don't understand the myth behind dpf?
I had few diesels before and only do 10-15 miles a day and never had problems with dpf
Dpf does two types of regens active and passive
Passive is on a long journeys which you wont even notice and active when car is being used for short trips
Where in this scenerio is dpf a problem
By me dpf problems rise cause of bad maintenance only
Diesel , petrol doesn't matter for short travels, obviesouly diesel still will be cheaper on fuel and that why most people buy it

 

[whitenemesis]

Diesels take longer to warm up and reach their advantageous mpg, so on short journeys they may not live up to that promise.

 

[Borys]

Would agree on bigger diesels like v6's
I drive temp car at the moment 2.0 diesel insignia and on my short journeys still average 44mpg

 

[whitenemesis]

What's the potential max mpg? Are you still falling short of its best?

 

[markjay]

...By me dpf problems rise cause of bad maintenance only...

How do you mean? What type of maintenance (or lack off) causes DPF failure?

 

[MBDevotee]

Diesels give all sorts of problems on regular short journeys. This is helped if once or twice a month they have a good blast down a motorway.

However - if you only do short journeys, why in gods name would you buy a diesel??

Given they are noisy, sluggish until the turbo comes in, (1800-2000 rpm) then 2000 rpm later they run out of puff (3500 - 4000 rpm), significantly dearer to service and massively more expensive IF they go wrong - and they go wrong far more often than petrols - can you please please please explain to me why you would buy one for low mileages.....

Over 20k per year I can see the advantage perhaps. otherwise....??????

 

[Borys]

How do you mean? What type of maintenance (or lack off) causes DPF failure?

Late oil service, no fuel filter changes ?????

 

[Borys]

Diesels give all sorts of problems on regular short journeys. This is helped if once or twice a month they have a good blast down a motorway. However - if you only do short journeys, why in gods name would you buy a diesel?? Given they are noisy, sluggish until the turbo comes in, (1800-2000 rpm) then 2000 rpm later they run out of puff (3500 - 4000 rpm), significantly dearer to service and massively more expensive IF they go wrong - and they go wrong far more often than petrols - can you please please please explain to me why you would buy one for low mileages..... Over 20k per year I can see the advantage perhaps. otherwise....??????

Went for a diesel as at least 3 times a year I go to Germany and Poland I would not benefit from a petrol....rest of the time are short journeys-is it a bad choice? Why diesels are being sold then in the first place.Manufacturer should advertise: diesel car don't buy it if you do short journeys :-0
This Insignia is quite fast, test drive it I'm well impressed

 

[meeeb]

Heard and read lots of dpf debates
I just don't understand the myth behind dpf?
I had few diesels before and only do 10-15 miles a day and never had problems with dpf
Dpf does two types of regens active and passive
Passive is on a long journeys which you wont even notice and active when car is being used for short trips
Where in this scenerio is dpf a problem
By me dpf problems rise cause of bad maintenance only
Diesel , petrol doesn't matter for short travels, obviesouly diesel still will be cheaper on fuel and that why most people buy it

I've subscribed to several threads on this subject and said virtually the same as you. I agree 100%

Anyone who thinks modern 6 cylinder diesels are noisy, sluggish and expensive is living in the dark ages.

A look at the new BMW 7 Series brochure to compare petrol with diesel - including purchase price & VED - will dispose of that myth.

I'll repeat, in 6 years of top end diesel ownership using on short journeys, I've never had a DPF issue.

You're right too about maintenance, which includes a monthly 30 minutes on a motorway, preventing DPF problems.

 

[markjay]

Late oil service, no fuel filter changes ?????

No sure why tired engine oil or blocked fuel filter will cause DPF issues.

Bad oil will cause internal engine wear, and blocked fuel filter will reduce power.

But it is not obvious how these will affect the DPF?

...You're right too about maintenance, which includes a monthly 30 minutes on a motorway, preventing DPF problems.

This is probably right, but if the 30 minutes Motorway run is unplanned and only done to keep the DPF in order, then this defeats the purpose of buying a Diesel due to fuel economy...?

 

[markjay]

I read on a Kia form that use of (cleaner) Premium Diesel fuel will eliminate DPF issues on cars that do not get to be driven on long journeys... not sure if this is true but either way I feed the Kia Shell V-Power Diesel, so we'll see...

 

[Borys]

No sure why tired engine oil or blocked fuel filter will cause DPF issues. Bad oil will cause internal engine wear, and blocked fuel filter will reduce power. But it is not obvious how these will affect the DPF?


Low ash oil ... ever heard of that? Try to put different in v6 diesel

 

[flango]

I've killed every DPFon all my cars, my mileage is 80% motorway and normally fast motorway speeds, yet all the DPF's on my cars for the last 8 -9 years have failed and had to be changed. The technology isn't that great and personally when I buy my next car which will be used, if its a diesel the first job will be DPF and EGR delete. They normally fail around the 80,000 mark

 

[chubbs111]

i had an 07 saab 93-1.9 diesel with 144000 on the clock,it had its original dpf and due to illness i was only doing short trips and never had a problem.

 

[meeeb]

This is probably right, but if the 30 minutes Motorway run is unplanned and only done to keep the DPF in order, then this defeats the purpose of buying a Diesel due to fuel economy...?

Well in some cases possibly, but as I'm retired enjoy driving and sometimes drive just for the pleasure of being in my car when DPF 'maintenance' is secondary, a jaunt down the motorway, which can often be fitted in with other duties, is no hardship.

Even driving purely for the purpose of clearing the DPF, 20 minutes once every couple of months at 50+ mpg is hardly going to majorly affect overall economy.

 

[Bellow]

Diesels take longer to warm up and reach their advantageous mpg, so on short journeys they may not live up to that promise.

But during warm up they will still be more efficient as CI being a lean burn technology combusts at a lower temperature thus losing less heat to the block/head. Precisely the opposite of SI which must richen the mixture to ensure combustion and at the higher combustion temperatures wastefully sheds heat to the block/head, hence the faster warm up. But during warm up it must be fed with an excess of fuel.

 

[markjay]

Low Ash oil....

While technically correct, I think it would be an exaggeration to say that use of wrong type of oil is the main cause of DPF failure... they also fail on perfectly maintained vehicles.

And I doubt that many people use the wrong type of oil for the car anyway - this might apply to DYI mechanics, but most people use garages (dealers or indies) who would use the correct type of oil.

My point is that poor maintenance is probably not a significant cause for DPF failures. I believe that poor quality Diesel fuel and short journeys are more likely to be a major contributor.

 

[meeeb]

I've killed every DPFon all my cars, my mileage is 80% motorway and normally fast motorway speeds, yet all the DPF's on my cars for the last 8 -9 years have failed and had to be changed. The technology isn't that great and personally when I buy my next car which will be used, if its a diesel the first job will be DPF and EGR delete. They normally fail around the 80,000 mark

Even when I was poor I never had a car with anywhere that level of mileage on, so maybe that's why I have no experience of DPF failure.

Anyway, with the government getting its knickers in a twist about pollution caused by diesel vehicles (ably contributed to by DPF removers!) I can see a gradual erosion of diesel economy due to increased direct and indirect taxation on such vehicles. They won't look for a practical solution like more efficient filtration, they'll try to tax it out of existence. Diesel vehicles are being banned in Paris and Berlin I believe, and the Green brigade will no doubt urge large cities in the uK to follow suit. Amongst other things it'll be another nice little earner for the government in the guise of environmentalism.

Hopefully manufacturers will come up with a solution, and as they have apparently spent millions developing diesel engines in recent times will make enough noise to make governments take a reasonable line.

 

[Teflonso]

I work the best of both worlds. I own my E350 and keep it mainly for long journeys. My C-Max is a lease car, gets used mainly for local journeys and if there is a DPF problem, it's someone else's.

But having owned a VW or two (and still have a 2.0tsi petrol), I'm familiar with much DPF debate over on the VW forum.

Firstly, unlike Star, VCDS diagnostics is relatively cheap to buy, very user friendly and you can plug in to do a DPF diagnostic, check ash content and even do a manual regen before the light comes on to say go to dealer.

Secondly, there's no shortage of people whining about a blocked DPF. But I'd say more than half the time it transpires they've either had a remap (serves 'em right then) or bought a car with a per-existing problem. The solution of choice is just to remove the DPF, which completely ignores the fact that it is now an MOT failure. Or...... just empty out the DPF and code it out then hope the tester is too dim to hit it with a screwdriver and listen for the ring.

My Passat was 5 years old when I sold it, had predominately done town journeys less than 20 miles and was DPF problem free. I ain't worried about my Merc.

.

 

[whitenemesis]

Forums attract those with problems..

One will always hear the bad news, very rarely the good. For every one on a forum with a particular problem there will be many 1000s happily motoring on without it...