Diesel Vs Petrol - john96
Now that they cost the same per litre, does it make more sense to go diesel, or do the complications of a modern diesel engine still outway the economy benefits ( for a private buyer at least!).
I remember reading that you need to drive around 15k per year to see diesel benefits, that must be much less now?
Diesel Vs Petrol - Glaikit Wee Scunner {P}
I've just returned to the diesel side after an 18 month break. Had a 140ps 2l Hyundai Coupe petrol which I could get up to 37mpg from, largely because I was scared to drive it hard with the unpredictable steering and grip. Now got a 140ps 2l Skoda Octavia diesel. About 1.57 times the torque, starting at much lower revs. Easy hill climbing and overtaking ,even when running in. ~45mpg from first fill up. I do about 14,000 miles per year and am aware of the EGR issues etc at higher mileages but so far I am loving it!
Diesel Vs Petrol - Andrew-T
In simple terms, the familiar diesel-petrol comparison was made by offsetting the extra cost of a diesel vehicle with its smaller demand for fuel. Diesel fuel was noticeably cheaper then (in summer anyway) so running cost was less; much less if you bought in France or Ireland.

Now, with fuel-price equality, only consumption counts - at least on a money basis. Comparing like cars with like, diesels should use about 20-30% less by volume (gallons). If one tries to do carbon accounting (by weight, i.e. Kg of carbon) the advantage is smaller because diesel is denser than petrol; it should however be about 10% better for the planet to burn diesel than petrol. IMHO, of course ...
Diesel Vs Petrol - Old Navy
does it make more sense to go diesel >>

It does not have to be a choice based purely on cost, preference can apply. Some people can afford (and own) big powerful cars but choose to drive a small one. I drive a diesel by choice. It would cost me less to run a petrol car.
Diesel Vs Petrol - MVP
Diesel is always cheaper in the summer as there is less demand for heating oil (primary heating fuel in the USA)

Diesel Vs Petrol - Snakey
I've run diesels for the last 3 cars I've owned and put around 100,000 miles on them. Now my mileage is down to around 18,000 a year I'm going back to petrol.

I like the driving characteristics of diesel but am heartily sick of the problems with the ancilliary devices such as EGR valves, DMF,DPFs and all that stuff. I know petrol engines also have their problems, but they tend to be a damn site cheaper to resolve.

Diesel Vs Petrol - Steve Pearce
I like the driving characteristics of diesel but am heartily sick of the problems with
the ancilliary devices such as EGR valves DMF DPFs and all that stuff. I know
petrol engines also have their problems but they tend to be a damn site cheaper
to resolve.

I've run diesel cars since 1995 and do around 30K a year. I've never once suffered any engine related problems.
Diesel Vs Petrol - Roly93
I think most diesels are reliable if they are worked hard, and flogged up and down motorways etc.
I think most of the problems people have with diesel unreliabilty is due to pottering around town and never giving the engine a good 'head of steam'.

I have done 200K in 3 separate diesel cars now and have never had an engine related problem.

I have to say though, that one thing that annoys me about diesels (if you buy them new) is the extreme length of the bedding in period. My A4 took over 20K miles before it returned true fuel economy, I am now getting low 40's around town and high 40's to 50mpg on motorway cruises, where I was struggling to get 40ish in the early days.
Diesel Vs Petrol - diddy1234
I agree.

10K miles and the diesel still feels a bit tight.
If I push the engine I get 47mpg and if I drive like a saint I get 52mpg

I suspect the gap will widen as the miles clock up.
Diesel Vs Petrol - akr
I suspect the price gap will widen again in the winter so the current diesel advantage will wane again.
I've just gone back to petrol after 4 diesel cars. My first 2 didn't suffer any engine related problems but suffered loads of electrical issues (both Golf Mk 4s). My 3rd (a Saab 93) with the 2.2 enging was dog rough but perfectly reliable and my 4th (a Saab 93 with the 1.9 150 engine in) was smoother and quieter but had EGR problems, a failed water pump and a failed alternator. I've no idea about engines so have no idea if these failures were connected to its being a diesel or not. What I do know is that they were expensive to fix.
I've now got a Mk 6 Golf GTi and its awesome. I've got 36/37mpg so far overall and compared to the wife's 93 diesel convertible it's a different world. I always thought that enging was ok and pretty quick but it now just seems lame (as you'd suspect compared to a GTI admittedly) but just downright rough in comparison.
Obviously, I'm still in the novelty value stage of the GTi but at the moment I suspect I'll stick to petrol next time round. It's just so much nicer to drive (and I don't wake the neighbours every morning like the wife does).
Diesel Vs Petrol - injection doc
I agree with Roly93, I have never had any issues with diesels or EGR valves & had them for years. My wifes latest fiesta TDCi is 2 years old & just staring to loosen up at 13k. It still returns 53 just pottering around & 60 on a run. The tourque from the 1.6 is just lovely & couldn't drive a petrol one, too much gear changing.
My own diesels never been an issue but always use Bp & snake oil once every 5k & never let the tank drop below a quarter.
Diesel Vs Petrol - madf
"I think most diesels are reliable if they are worked hard, and flogged up and down motorways etc.
I think most of the problems people have with diesel unreliabilty is due to pottering around town and never giving the engine a good 'head of steam'."

A well designed engine should not care.

Both our diesels have run for years (decade in one case) with mainly town driving. They are of course serviced by me..

No engine problems in 16 years.. touch wood..
Diesel Vs Petrol - movilogo
If you buy Kia or Hyundai diesel, you don't need to worry about engine issue for several years.

So, I think, in those cases, combined with enough mileage to justify choice, diesel is a winner.

Diesel Vs Petrol - Hamsafar
"MVPDiesel is always cheaper in the summer as there is less demand for heating oil (primary heating fuel in the USA)" - it makes sense, but certainly wasn't the case for the last few summers (or winters), In fact last summer, the gap widened in the UK.
Diesel Vs Petrol - cuthbert
This is a very open subject myself I prefer the torque of a diesel engine and just find it a more relaxed drive .

It also depends on the gearbox which attached to the car some of the power shift and DSG gearboxes will give you exceptional fuel consumption in comparison with a torque converter box

I have also noticed that some of the CVT gearboxes on petrol engines are returning diesel types economy.

To be honest it was hard to pick what to go for before its even harder to pick now
Diesel Vs Petrol - mattbod
A very tough question really. I love the effortless torque of my little Fabia VRS and the economy is great too. I think the effortless nature of a good turbo diesel has a lot to commend it but modern diesels are complicated and cost a kings ransom if they go wrong. My turbo packed up at only 36k and would have cost at least £1500 if Skoda hadn't stumped up the parts as goodwill. Then New diesels cost mire but hold their value better. I would say from a cost point of view if you do low to average miles get a petrol especially as Diesels take a ling time to warm up and hate being pottered around especially with particulate filters.

Cheers Matt
Diesel Vs Petrol - daveyjp
In the fuel market it's not diesel which has become cheaper, petrol has increased in price.

Apparently the demand for refined petrol has increased quite dramtically in the last 12 months or so pushing up prices.
Diesel Vs Petrol - The Melting Snowman
No more diesels in our household. Gone back to petrol and enjoying the smoothness, quiet cold starts and revs.

If I did 20K a year I might consider another but no way would I run a model common rail diesel out of warranty with all the silly technology such as DMF etc.

Diesel Vs Petrol - the swiss tony
On the way to work yesterday, I was reminded why I prefer petrols...

I thought I was following James Bond - but no... the smoke screen was created by yet another CDI with knackered injectors/pump/turbo/DPF (delete as applicable)
BTW, this wasnt some cheap thing that never sees a motorway.. ( I went past as he was joining the M40
It was an W211 E class facelift..... so that would have been the V6....

Edited by the swiss tony on 30/07/2009 at 07:27

Diesel Vs Petrol - andyfr
Both our cars are diesel and we do about 8,000 miles a year in each. We just love the torque of diesel and haven't bought a petrol model for... it must be nearly 20 years!
Diesel Vs Petrol - craig-pd130

I got my first diesel at it was more tax-efficient when the company car rules changed in 2002 / 3.

But I like the way they deliver their grunt, it's useful and satisfying.

I echo the points above about long run-in times, especially on Fords. My Mondy 2.0 TDCI has just hit 15,000 miles and in the last month economy has suddenly improved quite noticeably. For the last two tankfuls it's averaged over 45mpg, compared with 42mpg the same time last summer in similar conditions & usage.

In comparison my old Passat PD130 settled in very quickly, it was as economical at 5,000 miles as it was at 50,000.
Diesel Vs Petrol - madf
Mercedes diesels (V6s) were I believe prone to injector seat failure... which gave running problems and if untended lots of grief.

As I said a well designed diesel should give no problems.. That rules out Mercedes post 2000 to around 2006... Vauxhall, Renault on and off). etc.
Diesel Vs Petrol - diddy1234
I find driving diesel's less effort and more relaxing.

Although funny enough, just achieved my lowest mpg (43mpg) by driving like a saint (60mph a the most) !
Car has 10k miles so far

Next tank full will be ragging the car and see what difference the mpg is then.
Diesel Vs Petrol - bintang
There used to be a lot of discussion about carbon particulate pollution from dieslels, offsetting their negligible CO emissions. Has this problem, thought to be one reason for a big increase in asthma, now been resolved?
Diesel Vs Petrol - Number_Cruncher
>>Mercedes diesels (V6s) were I believe prone to injector seat failure...

All the CDi engines are so affected. The injector clamp and its tensioning bolt is a stunning piece of poor design. It's one bolted joint where a heli-coil repair in the Aluminium represents a significant improvement.

Diesel Vs Petrol - Andy P
I have to admit that I find the combination of 286bhp and 38mpg in the 335d quite a combination, particularly when mated to an automatic gearbox. Acceleration from any speed to a significantly greater speed is nothing more than amazing. Admittedly it doesn't have quite provide the same aural experience, it's not at all like a diesel - the noise is well well muted, and only when the 'box drops a few gears does it emit a very un-diesel-like roar.

I like.
Diesel Vs Petrol - Focus1.8TDCi
I've had one (major) problem with my mk 1 tdci focus - the dmf, cost £1k. But is that more to do with dampening the torque on the clutch and componenents and not a fault of the actual engine? Other than that it drives and performs brilliantly. I did try to tune it twice - once with a tuning box and then an ecu engine remap. Both made no difference to performance and the remap made it smoke a lot under heavy acceleration. I got it reverted back to normal.

The company said it was due to the air mass sensor. But the car drives perfectly normal. What does the air mass sensor do in a diesel?

Diesel Vs Petrol - diddy1234
here's your answer :-


Roughly speaking, It is used to measure air density, so the Ecu can calculate how much fuel needs to be injected to get an efficient burn.

hope it helps.
Diesel Vs Petrol - Focus1.8TDCi
How can I check if its functioning properly and do you think it was why my car did not work with the remap?
Diesel Vs Petrol - the swiss tony
As I said a well designed diesel should give no problems.. That rules out
Mercedes post 2000 to around 2006... Vauxhall Renault on and off). etc.

The V6's (06 on) are a worse engine than the straights ever were, Ive heard that the injector and turbo bolts are being replaced with wingnuts........
Diesel Vs Petrol - Shaz {p}
I have had a diesel car for a while now. Love the torque, and economy.

My 156 sw Jtd has been excellent. It has required a Egr valve change and a MAF, but it now has 107k on the clock. Good economy (40 - 46 mpg), a great noise and 175 bhp / 284 lb/ft is lovely. Only a V6 would come close, the 4 cylinder cars, although good for a petrol 4 cylinder wouldn't match it for everyday driving.
Diesel Vs Petrol - Rattle
Petrol for me :). I like free reving engines the noise makes me smile. I am wrongly with Jeremey Clarkson diesels.
Diesel Vs Petrol - Pat L
I've been a diehard diesel fan for a few years now but I've been driving my sister-in-law's Mazda 3 2.3 petrol here in Australia for the last 4 days and it's very nice! With petrol almost half the UK price I would be very tempted with a nice powerful petrol engine if I lived here.
Diesel Vs Petrol - glowplug
I don't think you can generalize, there's been/are some great/poor diesel/petrol engines.

Maybe it depends on your driving style and environment. I live in a very hilly city that suits my turbo diesel whereas with the wifes petrol car there's far more gearchanging but it suits her driving style.

Diesel Vs Petrol - Alby Back
I've been buying diesels for years and appreciate / need their benefits. Still prefer petrol engines though. If I didn't need the ecomomy I'd have a petrol in a heartbeat. I did run one for a while recently and much prefered the petrol engine, it was just some other things about that particular car I didn't get on with in the end.

I know this subject divides opinion among us but I'm very clear which I prefer. Just wish I could afford it with my crazy mileage. Also I do appreciate the not having to fill up every day aspect of a diesel.
Diesel Vs Petrol - Galad
>>If you buy Kia or Hyundai diesel, you don't need to worry about engine issue for several years>>

Providing that you have a Kia/Hyundai dealer service the car for the duration of the warranty at c£70+ an hour labour. As the much-respected 'Screwloose' once said on HJ (and where is he now?) 'modern common rail diesels will all come to a sticky end....'. EGR valves have to be cleaned/replaced; diesel particulate filters clogging up and having to be overhauled (ecolys fulid at c£25/litre) as a result of too much city driving (eg taxi drivers now reverting to petrol engines) and costing an arm and and leg to fix if, that is, they can diagnose the problem in the first place.

It leaves me wondering if the diesel fuel saving are offset by the repair costs charged by the dealers......
Diesel Vs Petrol - mattbod
I think on the balance of things you are right Galad. I love my 1.9 PD TDI but the turbo failure scared me.Add the extra complications you mention and I think a petrol would win out despite the higher emissions/tax.

Interesting abut what has been said about Merc Diesels. I am surprised about the durability issues of Merc Common Rail Diesels. I think the first 3.2 litre straight six was a lovely engine in the E class estate but would it be better to go for an E300 Turbodiesel with the 3.0 indirect injection 4 valve engine. I know these are good for astronomical miles if looked after. A mate has the 5 pot version of this modular engine in a C class with 280,000 miles. Somehow as you say I do not see todays Diesels making this very often. One of the first things people used to mention about oil burners was durability and long service life. You don't hear this very often now. Bought the Diesel magazine but doesn't say much on this either.

Edited by mattbod on 01/08/2009 at 11:25