Short journeys and DPF's

[Sp!ke]

My brother in law is looking at a replacement car and is looking closely at Audi A4 Diesels around the 2010 range.

Given that he lives in the middle of nowhere with no traffic and 99% of his journeys are less than 10 minutes long I was thinking that a DPF equipped diesel may not be the best choice and will likely end up causing him problems.

So my question is, are later DPF equipped cars still dogged by this problem or will he be OK?

 

[prprandall51]

From what I read, the latest diesels regenerate much more proactively than early ones, which just seemed to struggle along until the last minute before warning you that you had left it too late and your engine was kaput.

2010 is still quite early, I think.

Why not just be on the safe side and buy a petrol car?

 

[Sp!ke]

Why not just be on the safe side and buy a petrol car?

This would be my suggestion, especially as he will have little in the way of budget to repair any problems he might experience.

 

[Giantvanman]

Millers Oils News | DPF Cleaner

 

[chubbs111]

i owned a 2007 saab 9-3 with a dpf i only used it local and never had a problem.

 

[grober]

Petrol car for him every time. The fuel has less tax. Diesels are not desperately fuel efficient when cold . The interior heater often takes longer to work on short journeys . The cars tend to be more expensive to purchase initially. Only problem is that UK importers/ concessionaires seem determined to force us all to drive diesel cars by restricting the choice of petrol models they retail meaning nice secondhand ones are often rare. They seem to think that most UK motorists spend their lives pounding hundreds of miles up and down the motorways. While this may be true for business /company car users it frequently doesn't apply to the private/pleasure/weekend motorist.

 

[Chrishazle]

Watch out for those diesels that use Adblue - aka pigs urine - where the engine will stop if the Adblue tank runs dry! I understand Adblue is also expensive - about £9 per litre IIRC - and a litre does not last that long. I was recently reading about this on the PCGB forum (another VAG brand dammit!!), I think it was about the new Macan - and the tank holds 20 litres!!

 

[prprandall51]

i owned a 2007 saab 9-3 with a dpf i only used it local and never had a problem.

At the other end of the scale, our 2008 Fiat 500 diesel needed a new top half of the engine after 4500 miles from new, so significant was the damage caused by the DPF - and we had regenerated the DPF every time the light came on (a total of twice, IIRC).

 

[markjay]

I am in the same situation with my Kia diesel thst does only 1000 miles per year, mostly short journeys.

I read somewhere on the 'net that Premium fuels help reduce DPF issues by being cleaner and burning better - not sure if it is actually true, but either way I have been using only V-Power on the Kia and so far had no issue.


But as others said - why not just buy a petrol car?

 

[mbenz1]

As others have said, petrol engine is the safer option. But they really want a diesel, then I would suggest using premium diesel fuel with a shot of DPF regenerator bottle in the fuel tank every 1 or 2 months with a supplementary 15-20 run if possible. My dad uses Triple QX DPF Regeneration every two months along with a 15-20 min run and always premium fuel...so far this has proven to be good - no problems so far. Im not sure about Audi but MB DPFs in the 320 CDI engine are not thar problematic compared to the newer 350 CDIs and 250 CDIs, according to my local MB specialist. Maybe manufacturers want to make DPFs more problematic in the newer models, so that dealerships can earn some more.money??

 

[Dieselman]

Diesels are not desperately fuel efficient when cold . The interior heater often takes longer to work on short journeys .

Those two statements contradict each other.

The heater takes longer because the engine is using less fuel, which means it is more efficient.

 

[grober]

Those two statements contradict each other.

The heater takes longer because the engine is using less fuel, which means it is more efficient.

Agreed -- did not make myself clear. Diesels are more thermally efficient of course but when cold don't have the "super economy mileage" figures the manufacturers would have you believe. Think mid/upper 20's not mid 40's Of course petrol engines also have frightening consumption figures when cold but I would wager they reach their optimum operating temperature quicker than a diesel.

 

[prprandall51]

The rule of thumb figures used to be that a petrol engine was 50% efficient when cold and a diesel was 90% efficient.

I imagine that those figures have changed in recent years with all the tech that is now found in both engine types, but I would imagine that those figures aren't too far wide of the mark.

 

[markjay]

The rule of thumb figures used to be that a petrol engine was 50% efficient when cold and a diesel was 90% efficient.

I imagine that those figures have changed in recent years with all the tech that is now found in both engine types, but I would imagine that those figures aren't too far wide of the mark.

I have no idea regarding actual figures, but as an observation this information is incomplete without the figures for the time each type of engine takes to warm up to working temperature... and the mean, spread, and deviance of the efficiency factor across this time, to be precise.

 

[Dieselman]

The rule of thumb figures used to be that a petrol engine was 50% efficient when cold and a diesel was 90% efficient.

I imagine that those figures have changed in recent years with all the tech that is now found in both engine types, but I would imagine that those figures aren't too far wide of the mark.

A petrol engine struggles to make 25% efficiency at best, a car diesel is approaching 50%.
A petrol engine requires 400% fueling when cold, a diesel requires 110% when cold.

Figures c/o Bosch.

 

[meeeb]

Millers Oils News | DPF Cleaner

Or better still use Shell V-Power, or equivalent.

The behaviour of DPFs is surely the result of a variety of factors, not just journey length - e.g. what junk is put into the tank, how the engine is maintained, and the age/quality of the engine, i.e. is it a Fiat or a Mercedes-Benz, and how up to date is the technology?

As I have oft repeated, I have 6 years experience of using diesel cars on short journeys, a Jaguar and an E Class, and have had no DPF issues.

 

[mbenz1]

To the OP, you will find that some people have had no DPF issues in town driving but the number of DPF complaints are still huge (Mb) and I'm sure many other manufacturers. Its better to play safe and.buy either a petrol or a diesel without a DPF if possible.