Having just bought a diesel for the economy and , with a particulate filter , a relatively clean engine , I was interested to read the comments of Honest John in the Telegraph where he is rapidly falling out of love with diesel because -

1. the "diesel" premium on cars .

2. the increasing price of diesel over petrol at the pumps .

and most interestingly , as a result of his " knowledge of the industry " and letters from drivers in his reader columns

3. the increasing unreliability of the current generation of diesel engines because of the huge increase in technology being incorporated into them . He cited in particular Mazda who previously had a an enviable track record in reliability , but after about 70k were becoming a nightmare in some cases .

Interestingly , my daughter has a company Mazda , two cats , a husband and a job and a young son . Needless to say the car does not get a look in when it comes to care - twice I have quietly opened the bonnet , to find that there is no oil on the dipstick , anywhere ! ..... and the car is still going , plus the fact that there is a permanent light on the dashboard to say that there is water in an oil filter .

So I just wonder as to whether it is more a case of simple lifestyle that people , not in this community may I add , just do not look after cars nowadays and hence the increasing unrelability .

Discuss .......

I've heard quite a few stories about the newer oil burners just not being as reliable as the old ones...but it's obvious from the get go really, 10 years ago a good turbo diesel would break 100BHP, now they are sailing over 200...something has to give.

I am concerned however at the amount of miles we'll need to do in order to cover the extra costs of diesel at purchase and at the pumps.

I keep saying that I ned to write a little javascript web page that works it out for you. At hte moment the only attraction for diesel for me is the range, I could go to Glencoe in one push without stopping twice for fuel. But even that as I get older is less beneficial as it's quite nice to stop for coffee and fueling is not that much of an issue...but that's about the only swing factor at the moment.

Does anybody have any links to oliburner or petrol car calculators?

Well the slug is costing around £65 per tankfull, and I don't think the PD140 is all that economical in the grand scheme of things.

I am very seriously contemplating going to a smaller petrol family car and then get something small, light, fun to play around with at the weekends.

I do reasonable mileages, but watching the pump guage spin like a las vegas slot machine is starting to lose it's appeal.

I could get 340 miles out of a tank of tescos 99 on the vRS and get around 460 - 480 out of the PD140.

It's close cut, but with the current prices, I'm of the opinion that diesel has had it's day

you need to be covering big motorway miles for diesel to work out right now...

and even then not in all cases.

i have gone from a 2.7 hdi to a 1.6 turbo petrol. emissions are lower, fuel costs lower and performance / fun factor are up.

I suspect people moving from tdi170's to 1.4 tsi's would find similar....

In the case of Skoda it might work a little better with the CR perhaps being more economical but for the current PD units be it 140 or 170 they aren't as economical as people might wish. We run a PD140 now and it's the second one we've had and that certainly isn't economical.

As many are realising, the greater initial purchase combined with the higher price of fuel is making petrol more attractive again.

Which is a real pita as a dealer has just emailed me with a PD170 revo'd white and toys

Diesel up by 2.9 pence this week alone?

Let me grab some sugar and I'll do this dam maths, TaviaRS was taling yesterday about a small car daily runner 100hp swift and then when / if the need arises, hiring a tank for weekends away. It has a lot of sense + the cars are half the price!

Which is a real pita as a dealer has just emailed me with a PD170 revo'd white and toys

Diesel up by 2.9 pence this week alone?

Let me grab some sugar and I'll do this dam maths, TaviaRS was taling yesterday about a small car daily runner 100hp swift and then when / if the need arises, hiring a tank for weekends away. It has a lot of sense + the cars are half the price!

maybe a few more horses than 100 would be sensible..... but i got 47.8mpg from teeside to leeds with 175 petrol fed nags.... so it is possible....

My Octy 1.9TDI 105 (bought 2nd hand 6 months ago) is my first diesel car after a driving petrol cars since I passed my test 18 years ago.

What I wanted was a decent amount of torque for overtaking and I found that only a diesel can give you that PLUS decent economy. I think if I wanted a petrol car with decent thrust inthe mid range, the economy will take a hammering.

My last car was a Peugeot 306 1.6 and I think I got something like 400 miles from a 60litre tank. I get about 550miles from a 55 litre tank on my Octy so that's better PLUS I have far better performance! Did consider the 1.6FSI which is the closest petrol to the 1.9TDI but I read reports that it was a bit sluggish and the fact that you need Super unleaded to get best economy. I guess it depends on what you want. The 1.4 TSI 120 has had good reports but I hear that there are supply problems for VW on that one at the moment.

I used something I quickly knocked up in excel.

Can't upload it :(

so here's the formulae I'm using:

Petrol Diseasel

Annual Mileage 50000 50000

Avg MPG 36 41

Fuel Cost (ppl) 110.9 124.9

Annual Cost £6,992.86 £6,915.20

Petrol Diseasel

Purchase price 10000 11000

Annual Mileage 50000 50000

Avg MPG 36 42.5

Fuel Cost (ppl) 110.9 124.9

Annual Cost £10,326.19 £10,337.80

Cost is =(((B3/B4)*4.54)*B5/100) where petrol mileage is B3

For the second one I factored in purchase price, with petrol purchase price being B11

=(((B3/B4)*4.54)*B5/100)

you forgot that diesels tend to cost more to service, tend to eat their front tyres quicker - due to increased weight....

there is little in it.. where are a few years back the gap was clear...

depends a little on driving style... if you like the yo-yo torque surge of the diesel that makes the car "feel" fast or if you prefer the more subtle wider power band of petrol.....

Leaving aside servicing and tyres, I've done some calcs based on an Octy vRS TFSI and TDI. Figures look like this based on 20k per year. I've based the fuel economy on whatcar figures and those in the thread on here....

Petrol Diseasel

Annual Mileage 20000 20000

Avg MPG 35.8 45.5

Fuel Cost (ppl) 110.9 124.9

Annual Cost £2,812.77 £2,492.51

Petrol Diseasel

Purchase price 16782 17577

Annual Mileage 20000 20000

Avg MPG 35.8 45.5

Fuel Cost (ppl) 110.9 124.9

Annual Cost £8,406.77 £8,351.51

Being a bit of a maths geek thought I would try and work out the cost of running each.

I assume the following prices (all taken from cheapest in my local area on pertolprices website):

Unleaded 110.9p

Diesel 120.9p

Super Unleaded 115.9p

I then assumed the following economies (based it on a VRS spec Octy with a couple miles per gallon more if using super unleaded):

Petrol on unleaded: 33mpg

Petrol on super unleaded: 35mpg

Diesel on normal diesel: 45mpg

This then gave the following prices in pence per mile to run each way:

Unleaded 15.3p/mile

Super unleaded 15.1p/mile

Diesel 12.2p/mile

Interestingly the super unleaded can actually work out cheaper to run than normal unleaded despite the extra cost per litre if you can achieve the better fuel ecomomy.

The difference in list price between a diesel vrs and petrol one is £830 so to pay back this difference you need to drive 27k compared to a normal unleaded car and 29k compared to a super unleaded car. Over 3 years this just below the normal usage of 30k or so. hence I would conclude that it is still cost effective to run a diesel compared to a petrol (certainly does not cost you more). Also the longer distances between fill ups means less wasted fuel and time back and forth to the petrol station.

On an aside I have decided never to buy a smaller engined car as I never seem to get the fuel economy I expect. This is mainly due to my driving style and the fact I have to work a small engined car harder to make progress while driving i.e. in my VRS I do not have to accelerate too hard to get up to speed to join the motorway but in a smaller engine car I have to use far more throttle). I came to this conclusion after having a 1.2 Fabia for a week as a courtesy car. The first few days I was averaging 33mpg (the same as I used to get on my Mk1 VRS!!!!). Even after that shock the best I achieved was around 40mpg. Plus you have to enjoy what you drive and there was just no pleasure in driving such a slow small engined car.

So the economics could go either way with fuel at current prices. But what about the reliability issues in the OP?

Part of it is no doubt down to a lack of decent maintenance, which is due to ridiculous service intervals (cf. my previous posts on my views regarding the wisdom of the 18k / 2 year intervals on my last car!) and also to the relative cheapness and easy availability of cars, which makes some people view them as disposable items.

I also believe, though, that a lack of mechanical sympathy (and ultimately driver knowledge) comes into it. Back when the UK driving test was developed, it'd be highly-highly-highly unlikey that you'd end up driving a car that wasn't petrol, pushrod, and normally-aspirated by carburettor. Now, though, you can climb in a car and it could be petrol or diesel; normally-aspirated (mostly by injection but possibly by carb), turbocharged, supercharged, or turbo- AND supercharged; single overhead cam, double overhead cam, or pushrod (in a few cases); fixed valve timing or variable valve timing; etc. etc. etc. Each of these engines has slightly different power output characteristics that respond best to a particular driving style.

It brings to mind a recent post on dual-mass flywheels, where the poster in question complained that he suspected he'd just killed his second DMF, due to his predeliction for booting the throttle from low revs which was, in his opinion, the way to get the best out of a diesel engine. For an N/A diesel perhaps, but what's the point of having a turbodiesel if you drive it mostly off-boost? IMO, it's a bit like complaining that your V8 hemi has just snapped another conrod, because you like to drive it at 8,000 rpm all the time like you did in the Honda VTEC you had before it!

So anyway, my point there is that UK drivers will probably have been taught in a small, N/A, DOHC petrol, but there's no guarantee that's what they'll end up owning. Therefore, if they transfer that exact same driving technique to their own car, they may no be doing it any good...

you forgot that diesels tend to cost more to service, tend to eat their front tyres quicker - due to increased weight....

...

Which can be offset against the fact that diesels will now pay a *lot* less tax and are generally cheaper to insure than petrols.

Even with the current price of diesel my monthly fuel bills are still a lot less than when I was running with petrol power.

I get 550-600 miles out of a tank before I need to fill up, my last fillup cost £61.

My last set of front tyres on the 2.0TDi lasted 30K miles. The rear tyres are about 1/2 worn in the same time.

My last variable service was £165.

Road tax is £115,

I am still saving a lot of money running diesel power, and I reckon fuel would have to be around £2.50 a litre before it swings the other way in my case.

Car is on 51K miles, and apart from the current issue with the fuel temp sensor all is well.

Can't upload it :(

Jon rename the file .doc (it can be renamed .xls once downloaded) or put it in a Zip if you want to share it

It's still worth it for me on my current car.

I reckon that I'd be getting about 38mpg if I'd bought a 2.0FSI compared to the 50 I get now with my PD140

At £1.10 for unleaded and £1.22 for diesel that's 13.1p compared to 11.1p a mile on diesel.

Over 25k miles in a year that's a saving of about £520

I'd also save money on the tax , and the service costs are going to be very similar - I pay about £210 for a 19k miles service on variable so a petrol one won't save huge amounts.

The diesel may cost more to buy but I'll get the large majority of that back when I sell it on so I'm doing ok.

As long as it's cheaper or the same cost I'll stick with diesel as I prefer the way they drive to petrol.

It's not as clear cut as it was when I bought the car though , and some of the new small turbo petrol engines are getting cheaper to run now that there's a 10 percent extra cost for diesel.

If you look at the figures for the 1.4t in the Jetta it's as quick as the PD140 and not far off being as economical

rename as .xls or open with excel...

fuel.txt

4 DMF's and as many clutches caused by the DMF going in a year.

DMF's, turbo chargers, lots of electrics, DPF's and goodness knows what else mean that the current generation of dervs are not great.

The CR engine may hopefully fix some of the TDI's woes if they have properly engineered it to get over the problems.

The way this is going I'm thinking of a 406 2.1 XUDt for a few years when it's time to change.

also remember that you should not factor in the full extra cost of a oil burner over a petrol - as you will get much of the difference back when you sell the car again.

4 DMF's and as many clutches caused by the DMF going in a year.

DMF's, turbo chargers, lots of electrics, DPF's and goodness knows what else mean that the current generation of dervs are not great.

The CR engine may hopefully fix some of the TDI's woes if they have properly engineered it to get over the problems.

The way this is going I'm thinking of a 406 2.1 XUDt for a few years when it's time to change.

:eek::eek:

also remember that you should not factor in the full extra cost of a oil burner over a petrol - as you will get much of the difference back when you sell the car again.

wouldnt bet on with the shift away from diesel taking hold....

Being a bit of a petrol head, I was reluctant to buy a derv, but I am currently running my Fabia VRS as a (personal) company car, after selling my Golf GTI Anniversary 1.8T, which I loved, I was getting 350 miles from a tank if I was lucky. The Fab is around £10 cheaper to fill up (was then!) and I'm getting 450+ from a tank, plus cheap tax and insurance, so it works out better for me, it just hurts when I see diesel for 132.9P in my local Shell and V Max 115P!! It makes me think, did I make the right decision?

Just based on fuel costs alone and doing 11k a year still works out just over £300 better for me personally. (49MPG is based on my long term average)

Petrol Diesel

Mileage: 11,000 11,000

MPG: 36 49

£/Gal: 5.042 5.496

Annual £1540.61 £1233.80

Cost

The CR engine may hopefully fix some of the TDI's woes if they have properly engineered it to get over the problems.

Doubt it, if it's anything like the rest of the world's commonrails. DMF, EGR, swirl flaps, and DPF. Crap, all of them.