Why isn't it recommended to get a diesel...

Third Opinion · 1 Aug 2013 at 08:29

Lashout_UK said:
How many people have had problems with DPF filters on here, out of interest? I do wonder about the true scale of the issue. I asked around the office and could only find one person that had suffered a fault with a DPF in their car - but it was caused by a fuelling problem rather than numerous short trips.

Just curious

Mine has done 65k now, not that many long runs. Missed a service etc. 7 years old.

The result is my DPF is 18% full. I have never seen the light come on, never felt a regeneration.

If the worst ever happened and I had to replace it, it would cost £357

http://www.ebay.co.uk/itm/Fiat-Sedi...ar+Make:Fiat|Model:Sedici&hash=item2ec64b1ffd

Not the £1000-£1500 figure that is often banded about.

It would interest me just how many have been replaced when when they didn't really need doing. I had a sensor go that cost £15, the initial dealer diagnoses was it needed a new DPF.

Freefaller · 1 Aug 2013 at 08:55

Catanonia said:
I have heard that MPG goes up with ambient temperature, ie Diesels not so good on winter days compared to summer days in terms of mpg.

Bull or true ?

Warmer air = less dense = less fuel burned as there is less oxygen per cubic centimeter etc...

Colder air = more dense = more fuel burned but more power.

Freefaller · 1 Aug 2013 at 08:57

In my old job, I was doing 30+k miles a year - a diesel made sense as I was returning high 50s to low 60s mpg. And of course my mileage was paid for but economically it made more sense through company car tax etc...

However, I would never own a diesel myself, the amount of long distance runs I do a year now wouldn't really make me flinch - and heck 30mpg on a motorway run isn't that bad certainly not for the few times I have to do it. I'd rather have a nicer car than one that is particularly efficient.

paradigm · 1 Aug 2013 at 09:04

Freefaller said:
I'd rather have a nicer car than one that is particularly efficient.

Had you said nicer engine I'd have understood.

But you are somehow saying that nice cars are only available with petrol engines? :confused:

Simon · 1 Aug 2013 at 09:29

Freefaller said:
Warmer air = less dense = less fuel burned as there is less oxygen per cubic centimeter etc...

Colder air = more dense = more fuel burned but more power.

It's more to do with the warm up time than combustion events in normal engines.

Lean burn can be affected by the ambients mind you

blitzwing85 · 1 Aug 2013 at 09:42

I've just had the Emissions Control Light flag up on my dash. Got a quick free check at local garage and came up with 4 errors all related to the DPF.

Note: All my driving is around town - so it's to be expected.

Oddly though, the light came on the one day I did 150 miles in it!!
Then a few days around town and it went off.

Then I did another 60 minute trip @ 70mph and it came back on!

My milleage is only 6000 pa and I got around 50-55mpg before re-map. Now it's more consistantly at 55mpg on average. Still totally not worth it.
Chaging it soon and will be going for a Petrol

Freefaller · 1 Aug 2013 at 09:52

paradigm said:
Had you said nicer engine I'd have understood.

But you are somehow saying that nice cars are only available with petrol engines?

I kinda did mean that - in terms of driving I much prefer the feel of a petrol engine. I wasn't very clear.

Don't get me wrong, I've been in some lovely 7 series, A8s and similar which are gloriously comfortable, well specified and to be fair fantastically rapid - however the v6/8 diesels aren't exactly that frugal.

The big hoopla over diesels being cheaper and more efficient is well past it - though if it were like France where diesel is still significantly cheaper than petrol things may be different. In this country? Hardly.

Again, as I said, if driving for 10s of thousands of miles every year is needed then there could potentially be some marginal benefits.

Freefaller · 1 Aug 2013 at 09:52

Simon said:
It's more to do with the warm up time than combustion events in normal engines.

Lean burn can be affected by the ambients mind you

Fair point.

kevpuk · 1 Aug 2013 at 11:06

Freefaller said:
<snip>...however the v6/8 diesels aren't exactly that frugal....<snip>

Not as frugal as smaller engines, no, but in comparison to what an equivalently powerful petrol engine gives they are, surely?
Taking my car as an example (I have only had it for a week, mind :eek:

) - I think I would struggle to find a car capable of sub 6s 0-60, massively quick 30-70 etc. and still be able to return decent mpg.

I have managed around 38mpg so far, which is below what I would expect, based on approx. 80% motorway on cruise at 90

rolleyes

and the rest either short urban runs or stuck in stop-start M25 queues etc. Seems pretty decent to me, and I just can't think of a similarly powerful petrol that would match.

And I should stress that I have never had or even close to wanted a diesel before, so am a truly new convert......

Jonnycoupe · 1 Aug 2013 at 11:31

kevpuk said:
I have managed around 38mpg so far, which is below what I would expect, based on approx. 80% motorway on cruise at 90 rolleyes

I'm suprised Jaguar do so well on customer satisfaction if the buyer has expectations like that.

kevpuk · 1 Aug 2013 at 11:38

TBH, I had the 'magic' 40mpg in mind.....and I think I will likely attain it, once I get over the fun-of-the-new-car-driving thing

NathWraith · 1 Aug 2013 at 12:00

[TW]Fox;24696644 said:
You can make any car display that for a photo if the conditions are right and you hit reset at the right moment. I think its fairly safe to say that your car is not doing almost 80mpg across the entirity of any meaningful journey.

aha I'll have a go at this later. 100MPG I come

Freefaller · 1 Aug 2013 at 12:52

kevpuk said:
Not as frugal as smaller engines, no, but in comparison to what an equivalently powerful petrol engine gives they are, surely?
Taking my car as an example (I have only had it for a week, mind ) - I think I would struggle to find a car capable of sub 6s 0-60, massively quick 30-70 etc. and still be able to return decent mpg.

I have managed around 38mpg so far, which is below what I would expect, based on approx. 80% motorway on cruise at 90 rolleyes and the rest either short urban runs or stuck in stop-start M25 queues etc. Seems pretty decent to me, and I just can't think of a similarly powerful petrol that would match.

And I should stress that I have never had or even close to wanted a diesel before, so am a truly new convert......

It's a fair comment, but to me there are more important things than MPG

Besides on a long motorway stretch, mid 30s vs low 40s doesn't give me a frisson of excitement to want that extra few mpg

Have you tried cruising at 70 rather than 90? I found my diesel cars to perform much better at that speed.

Having had a handful of powerful cars, hitting mid 30s mpg is more than achievable - heck motorways are boring anyway, and doing any more than 70 is pointless - and if you're worrying about mpg on the back roads, then we're clearly have different priorities as to what we want from our cars!

Zeed · 1 Aug 2013 at 13:01

We got new ford minivan last year 1.5 diesel or something. Its doing City driving all the time.
So far its been back to for 4 yes FOUR times for that ****** filter cleaning !!!! Its done 3000 miles. Engine Goes in to malfunction mode and cuts timing and turbo off almost completely. Had to call AA each time to have it taken away to dealer for that ****.

WARNING DONT BUY NEW DIESELS FOR CITY DRIVING !!!!!

Uriel · 1 Aug 2013 at 13:05

NathWraith said:
aha I'll have a go at this later. 100MPG I come

What? Like this you mean? Petrol too!

(taken about 1 mile after the trip computer auto reset after a fill up a year or two back and amused from the novelty of getting over 3 figures)

Just to be clear, I have never got more than 60mpg on an actual tank.

J1nxy · 1 Aug 2013 at 14:08

kevpuk said:
TBH, I had the 'magic' 40mpg in mind.....and I think I will likely attain it, once I get over the fun-of-the-new-car-driving thing

On a decent run at 75 ish cruise I could get early-mid 40s out of my 1st XF. The new one with the 8 speed box gets high 40s-50 on a similar drive. Over the last 7000 miles I've averaged 36mpg.

kevpuk · 1 Aug 2013 at 14:10

Freefaller said:
<snip>Have you tried cruising at 70 rather than 90? I found my diesel cars to perform much better at that speed<snip>

TBH, I don't usually travel at this speed, even with clear roads. I expect that when I drop it down to indicated 80, I will fair noticably better.

But, mpg is not my be all and end all either...just a nice bonus.....I claim 45p/mile from MyCo for all my business related travel, and most of this is squirreled away to pay for the inevitable scary bills I will eventually face :rolleyes:

J1nxy said:
On a decent run at 75 ish cruise I could get early-mid 40s out of my 1st XF. The new one with the 8 speed box gets high 40s-50 on a similar drive. Over the last 7000 miles I've averaged 36mpg.

That will do me nicely

Then, in a year or so, I can look at an 8-speed......

Freefaller · 1 Aug 2013 at 14:18

If I still had a company car and doing the miles then a diesel is what I'd choose. Otherwise I don't see the point.

However, I live in London, and use pubic (sic) transport and so I can afford to have a gas guzzler as my mileage is low - even with a few long journeys a year.

Simon · 1 Aug 2013 at 19:25

What is your gas guzzler then ?

Yaayuh! · 1 Aug 2013 at 21:32

Uriel said:
VAG 1.2 and 1.4 TSIs are pulling some impressive figures with fairly large cars like the Octavia and Superb averaging in the mid 40s mpg.

Unfortunately the Audi A1 1.4TFSI (2011) is getting rather standard 37MPG on average 35% Town 65% Motorway.