# Compairing Diesel to Petrol. Need Help!!!



## lee. (Jan 16, 2008)

Morning Guys,

Looking for a little help, It's safe to say my brain is not working today. I'm trying to work out the difference between a Diesel and Petrol Car.

I'm looking at buying a new car and will be keeping it for 3 years as it's on a PCP

The Difference in cost between the Diesel and Petrol version is £2355.00

The average fuel prices today are:- Diesel £1.4557 and Petrol £1.3978 so a difference of £0.0579

The MPG of the Diesel car combined is 55.4mpg and the petrol 38.7mpg

Both fuel tanks carry 66ltrs of fuel

Let's say for example that the Diesel will cost me an extra £30 per month over 3 years on finance as it's a more expensive car but how much more will I pay each month to run the petrol as it get's a lower mpg. Let's base it on running for 3 years at 10,000 miles per year.

I hope someone can help me with this as I would love to know the answer but my brain will not allow me to find that answer today for some reason.

If I have missed any valuable info then let me know and I will try my best to answer.

Thanks in advance.

Lee.


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## DMH-01 (Mar 29, 2011)

Another thing to take into consideration is the cost of tax. Tax for my petrol E46 was £260 for a year but now with my diesel it's £210.

This tool has been quite handy for me before...

http://car-costs.parkers.co.uk/


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## init6 (Mar 28, 2012)

£300 or there abouts cheaper to run the diesel over the 3 years. Will show you my working if I can get this to format properly.


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## Will_G (Jan 23, 2012)

Done a few quick calcs which I think are right although best verify them yourself. Hope it helps

Diesel Petrol 
55.4 38.7 mpg
12.19 8.51 mpl
10000 10000 miles
820.48 1174.54 litres of fuel
1.4557 1.3978 cost per litre
£1,194.37 £1,641.77 Fuel Cost / year
£447.39 Difference / year
£360.00 Increased Finance/year
£87.39 Overall Difference/year


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## Kerr (Mar 27, 2012)

The petrol version will 775.2 gallons over 30000 miles costing a total of £4919. 

The diesel version will use 541.2 gallons costing £ 3578. 

The diesel save £1341 in fuel. 

There is honestly no point buying a diesel if you only do 10k a year. Buy a car with a smoother refined petrol engine. 

You will also see diesel increasing in price faster than petrol.


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## sirkuk (Mar 5, 2012)

You're asking us to do basic math?

The diesel will do approximately 800 miles to a tank whereas the petrol will do approximately 560 on the numbers you have given.

The diesel will cost about £96 to fill up whereas the petrol will be about £92.

Over a year that's 12.5 tanks of diesel at 10,000 miles which is £1200. The petrol would need 17.9 tanks of petrol at 10,000 miles which is £1646.80.


£30 extra a month though and you might as well say the diesel is costing you £1560 a year in fuel. £86 better off in that respect.


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## jim55 (Nov 12, 2008)

insurance as well ,its normally a bit less to insure a diesel than a petrol (equiv model),tbh a lot of petrols now are pretty similiar mpg so i dont think theres as big a gap as a lotta people think ,but in gen id say diesels are obv cheaper to run ,it depends on the mileage ur doing ,if ur doing loadsa miles it will prob b worth it going for a diesel,but for gen use and low mileage theres not much in it


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## Multipla Mick (Feb 5, 2006)

Don't forget other variations that may exist in running costs between the two, such as road tax, insurance, servicing and depreciation. Trying to fully weigh the two variants up can stretch my poor brain way beyond it's design limits :lol:


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## Ninja59 (Feb 17, 2009)

do not forget the potential for more expensive servicing on the diesel...and some wear tyres quicker because of the greater torque. oh and ofc the additional purchase costs involved in diesel but when you sell you tend to get some of this back...


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## jim55 (Nov 12, 2008)

btw iv got a diesel and getting it remapped was something i was aware of when buying ,app the gains are a lot more on a td than a petrol ,torque is the key and a remapped diesel has loads without affecting mpg


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## timprice (Aug 24, 2007)

may i also ask which car?

Depreciation would be a factor depending on if you plan to 'buy it' at the end of the PCP deal, or give it back and get something else.

For example, my Passat is worth more in Diesel form than it would be in Petrol, purely because the diesels are more in demand.

If you're buying a Polo for example, the most popular ones are the 1.2 and 1.4 petrol and as such will hold their value better.


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## Dixondmn (Oct 12, 2007)

Basing the figures on 10k miles per year i wouldn't even consider a Diesel.


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## m1pui (Jul 24, 2009)

What car's are you looking at and what kind of driving do you do? 

The MPG difference between the petrol and the diesel could be closer still if you do a lot of urban driving. I had a e46 320D and whilst I did a fair bit of driving, the majority of it was around town. The OBC showed I was getting something like 36mpg. Sold it to my cousin who does a long commute to work every day and he's getting mid/high 40's from it now.

Looking at this with a bit wider point of view, and I know there's a million variables but why not try a couple! lol

Check what size tyres each car is using if they're the same car but different trim levels.

The other half has a 1-series with 16" wheels, if she had got one with 17" wheels the tyres, like for like, are roughly about £40-50 a corner more expensive. (£98 vs £140-150)


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## lee. (Jan 16, 2008)

Wow,

What a response,

Thanks guys I knew I could count on you.

I will go study the replies in detail now and jump back onto this post.

Thanks again,

Lee.


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## The Cueball (Feb 8, 2007)

I don't think it's that simple or easy to compare the 2 different cars, specs etc... so many costs...can't just base it on fuel costs... has to be ALL the running costs including depreciation... 

But, I had always been told that the "switch" from petrol to diesel came in about 15k and above miles per year?!?!

Not sure how true that is...

:thumb:


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## timprice (Aug 24, 2007)

The Cueball said:


> But, I had always been told that the "switch" from petrol to diesel came in about 15k and above miles per year?!?!
> 
> Not sure how true that is...
> 
> :thumb:


Yeah i've heard the same. I think it also boils down to how you like the power delivery on your cars.

I love the low to mid-range shove of a diesel that you just can't match with a petrol engine (well unless its a massive 4.0 V8 or something!), but others like the smooth delivery of the petrol engines.

Personally, i dont think i will every buy petrol again but each to their own.


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## lee. (Jan 16, 2008)

I think I have fopund the answer I was looking for. I know other costs have to be taken into consideration but on Fuel alone at 10K it looks like Pertrol is prob the way forward in terms of keeping the monthly outgoings down.

If I was doing 15k+ then Diesel would be the better option.

Once again thanks for the quick and huge response, It's very much appreciated.

Lee.


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## SteveyG (Apr 1, 2007)

What are you used to driving? As recent posts on here have shown, you may not like how one or the other drive - so don't base you decision just on numbers!


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## lee. (Jan 16, 2008)

I have driven both but the only difference is the type of purchase. I have always bought my vehicles outright if possible or taken them on a HP but this time it's all about the PCP.

I'm looking at things like how much the car will be worth as a forecast in 3 years when I hand the veichle back and trying to compare the two engine types on so many levels.


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## SteveyG (Apr 1, 2007)

Personally I'd try to consider the drivability first and foremost. You might save yourself £500, but if it ends up driving like a sack of  then you'll be wanting to get rid the whole time!

What car is it by the way?


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## Spoony (May 28, 2007)

I bought a diesel because I do the miles (about 25k last year!!!)

But I'd suspect at =<10k a year then it's not worth considering the diesel. If go petrol if it were me.

Which car?


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## m1pui (Jul 24, 2009)

I don't think he wants to tell :lol:


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## SteveyG (Apr 1, 2007)

Probably a Golf :lol:


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## SteveTDCi (Feb 8, 2006)

If your looking at PCP then the difference in list price won't be so apparent, sometimes you will find the rates are lower, but add up the total cost you would pay. This includes the deposit - this will be higher on the diesel and alo all of the monthly rental, assume you want to walk away so don't worry about the mgfv. 

Take into account the types of trips and mileage, lots of short trips around town go for petrol, long trips go for diesel. The cut off used to be around 16k but it's dropped in recent years as petrols mpg has improved.


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## GR33N (Apr 5, 2009)

SteveyG said:


> Probably a Golf :lol:


Doubt it with a 66L fuel tank, but obviously that was the most hilarious comment ive ever read in the history of time. Obviously what we should all be doing is being just like you, wouldnt life be so interesting.


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## SteveyG (Apr 1, 2007)

GR33N said:


> Doubt it with a 66L fuel tank, but obviously that was the most hilarious comment ive ever read in the history of time. Obviously what we should all be doing is being just like you, wouldnt life be so interesting.


  Who shat on your parade today? It was said in jest, as with all the Golf hating recently he probably would be opening himself up to more abuse.


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## PugIain (Jun 28, 2006)

i bought a diesel because i didnt want a petrol 407.couldnt find one anyway!
besides i keep my cars so resale value is not important to me.


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## SteveTDCi (Feb 8, 2006)

PugIain said:


> i bought a diesel because i didnt want a petrol 407.couldnt find one anyway!


Thats because they put the hamsters in my 206


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## PugIain (Jun 28, 2006)

SteveTDCi said:


> Thats because they put the hamsters in my 206


dont see many posts complaining about french hamsters on here though.
unlike their "reliable" german cousins


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## SteveTDCi (Feb 8, 2006)

mine ate the cat and cost me a lambda sensor, the cat was empty, nothing in it  i also have German and Spanish in the fleet, but getting tempted by something Swedish or Italian


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## shane_ctr (Dec 17, 2006)

I have a e90 bmw 320d more becsuse of the way diesel delivers the power over the petrol model


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## PugIain (Jun 28, 2006)

SteveTDCi said:


> mine ate the cat and cost me a lambda sensor, the cat was empty, nothing in it  i also have German and Spanish in the fleet, but getting tempted by something Swedish or Italian


i just sold my 406 to my bro.4 years and apart from service,mot,insurance,petrol and 2 sets of front tyres it cost nothing to run.no repairs at all.shes on about 110k now.


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## greenwagon (Dec 31, 2008)

I personally like the way a performance diesel drives and the torque is more rewarding then a lower powered petrol engine 

You need a exact fixed price breakdown for 3years of servicing a cam belt change could be £300 

I purchased a wrxd Subaru rather then a STi petrol and it worked out at something like 10k better off for me over five years 

You might increase your mileage as well hence diesel would be better if you change your job or circumstances as well 
Also resale vaue should be bought into the equation too for the final figure


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## SteveyG (Apr 1, 2007)

greenwagon said:


> I personally like the way a performance diesel drives and the torque is more rewarding then a lower powered petrol engine


Not really a fair comparison though. A performance petrol is going to drive better than a lower powered diesel too.


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## SteveTDCi (Feb 8, 2006)

If you lease resale value is already included in the figures, when you lease you basically pay off the depreciation. There are so many different ways of looking at it.


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## Duke Wellington (Dec 1, 2009)

Something else for you to consider is which fuel is compatible with your regular drive:

Thanks to EU regulations new diesels have in the exhaust system a Diesel Particulates Filter (DPF). The DPF collects soot that from time to time goes into a regeneration mode; this super heats the trapped soot and burns it off. Regeneration occurs when soot builds up to a level that the emissions management system decides it needs to. If this happens while you are stuck in traffic, a full regeneration will not happen, it works best while you are driving at a constant high speed on an A road or Motorway. 

If you live in an urban area, your drive consists of short school runs, the commute is a constant stop start and you can’t see yourself driving at a high speed on a regular basis you will have problems with soot building up in the DPF and not being able to regenerate. This soot will build up to a level that a normal regeneration cannot occur; you will need to take the car to a dealership for them to run a DPF regeneration that will cost you money. If this happens often the DPF will end up knackered and it will need a very expensive replacement.

A lot of people bought diesels without knowing about this are experiencing DPF problems because their type of driving is not compatible with a DPF fitted diesel car, they would have been better off buying a car that runs on petrol.


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## dann2707 (Mar 25, 2011)

These emission reducing systems (EGR, DPF) are such a pain don't you think, nothing but costly in the long run.


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## alanp (Feb 3, 2012)

as duke said dpf is the biggest pain ever on modern diesels. I used to say that diesel was the way forward but now have changed my tune and say unless you are doing lots of long journeys stick with petrol. 

doing lots of short journeys and not getting a diesel engine up to running temp for a decent period of time just causes you more problems in the long run. I would advise the petrol it "should" give you the most trouble free motoring.


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## PugIain (Jun 28, 2006)

Unless you're clever and bought a modern diesel that doesnt have a DPF...


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