Opinions - Diesel v Petrol - How undesirable is adblue?

[aSteve]

I would like to solicit opinions from the car-community about a decision I'm finding difficult.

For the past 12 years, I've been a very happy driver of a 2010 (Gen-1) VW Passatt CC. Mine was the 170bhp diesel with a DSG gearbox. The only things I wish were different are that I'd like a sunroof/panroof and all-wheel-drive. The things I like most of all about my current car (in order of importance to me): huge range - big tank and fuel efficient; comfortable upmarket interior; enough performance (8s 0-60) and a pleasing unassuming exterior.

A week ago, a car drove into the back of me while I was waiting at traffic lights. My insurer wants to write off my car... and while I may be able to buy it back as a category-N write-off... I feel it may be a better idea to bite the bullet and replace it with something newer. I've a self-imposed ~£20K budget (as I'd prefer to have no more than that parked in a random car-park) but would want the car to provide me over a decade of reliable, comfortable, motoring.

I've considered BMW 3,4 and 5 series; Mercedes C and E class ; Audi A4,A5 and A6 and the VW Arteon - all with a focus on diesel cars with all-wheel drive.

I've been put off BMW as the reasonably recent models I've looked are all described MHT. I assume this mean they are hybrid diesel/battery-electric vehicles... and I feel I'd want the simplicity of diesel-only from the perspective of long term maintenance costs and general reliability.

I love the appearance of the Mercedes W213 coupe - when I think with my impractical heart. When my head engages... I worry that they seem flashy... and wondered if the image of such a car would attract unwanted attention - for example if I were forced to park in a rough neighbourhood.

While the Audi options felt they might be OK - the ones with appealing specifications sometimes seemed to stretch budgets. Considering the Arteon, while the 4motion cars are rare, they do appeal (especially when they have a pan roof) and the specification - especially of the 2.0 diesel - on paper at least - meet my desire for huge range, fuel economy and upmarket interiors.

Having almost convinced myself that a diesel 4-motion Arteon is what I need to buy... a friend reminded me that it would have ad-blue. This caused me to have doubts that I was making a sensible decision. I've heard negative stories about diesel adblue systems (all, perhaps by chance, with VAG cars) relating to high adblue maintenance costs and much lower fuel efficiency relative to non-adblue predecessors. If a fair assessment - might this cause me to be disappointed with an adblue car... where reliability and range are top of my list of priorities?

An alternative to the ~190PS diesel Arteon is the ~280PS petrol variant. If performance was near the top of my list of priorities... it would be the obvious choice... on paper, at least. Conversely, as I prioritise range/fuel efficiency and I rather like the relaxed sensation I get from my existing diesel powering my DSG gearbox... this isn't an easy compromise to make.

To what extent is a 2.0 (170-190PS) diesel car with adblue going to be less reliable, or more costly to maintain, than an equivalent car without adblue? Given that I anticipate being no more personally satisfied by 280 relative to 180PS - if delivered through a good automatic gearbox... and that I'd need to compromise on range and fuel efficiency if I chose a petrol over diesel car... it's not obvious to me what is best. I wonder if the answer to this question is going to be the same if asked about other makes/models as it is for the 2.0 diesel vs 2.0 petrol Arteon.

So... opinions... does it make sense to reject diesel in favour of petrol... when the highest priorities (in no particular order) are reliability, range/fuel-efficiency, and long-term total cost of ownership? Are the negatives associated with Adblue more relevant to VAG cars than other manufacturers?

[legless]

I can't comment on the long-term reliability of Adblue, as I've never had a car long enough for it to present any issues, but I have had two Arteons in the past - a 190PS diesel and a 280PS petrol, both 4motion DSG.

I found the diesel infuriating. The step-off throttle lag was diabolical, and it almost ruined the car for me. The petrol had no such problem.

It may have just been the example that I had, so it's worth test driving one to see if you get on with it.

[this is my username]

How bad is the damage? Insurers wanted to write-off our car with a £7k payout after a rear-end shunt. A local smart repair guy fixed it within a day for around £1k, the insurance company paid for it.

Insurance repairs typically involve new replacement parts instead of repairs, plus hire cars etc so costs escalate quickly.

[Robertb]

Adblue and diesel engines add an extra layer of complexity and maintenance cost, and the fuel is more expensive.

Modern turbocharged petrol cars seem to offer much of the advantages ie torque and economy, but then these days have also got things like GPFs which can be problematic.

I can’t comment on VAG adblue systems but the one in my CLS 350d hasn’t so far caused a problem, touch wood.

[Ry.Clarke]

I have never had an issue with ad-blue but I know lots have. 230k now and never even a warning light for it.

From my own observation it seems to be BMW, Peugeot and Audi that have had the most issues with it.

I cannot comment further on the Germans as I refuse to pay the premium, but I wouldn t be put off one, although admittedly I would pick the Mercedes.

Edited by Ry.Clarke on Thursday 9th October 07:38

Edited by Ry.Clarke on Thursday 9th October 07:40

[Ry.Clarke]

this is my username said:

How bad is the damage? Insurers wanted to write-off our car with a £7k payout after a rear-end shunt. A local smart repair guy fixed it within a day for around £1k, the insurance company paid for it.

Insurance repairs typically involve new replacement parts instead of repairs, plus hire cars etc so costs escalate quickly.

You missed out there. Should have bought it back and pocketed the difference. The value in the car is shot either way:

[aSteve]

legless said:

... I have had two Arteons in the past - a 190PS diesel and a 280PS petrol, both 4motion DSG.

I found the diesel infuriating. The step-off throttle lag was diabolical, and it almost ruined the car for me. The petrol had no such problem.

I had to google 'step-off throttle lag' - but now I know what it means... I don't think I've ever recognised having experienced the problem. Perhaps I'm just a boring type who seldom engages in spirited driving... Another possibility is that the 2.0 (170) non-adblue diesel I've loved for over a decade (the one at the heart of the diesel-gate scandal) really was better than more modern 2.0 diesels.

[aSteve]

this is my username said:

How bad is the damage? Insurers wanted to write-off our car with a £7k payout after a rear-end shunt. A local smart repair guy fixed it within a day for around £1k, the insurance company paid for it.

Insurance repairs typically involve new replacement parts instead of repairs, plus hire cars etc so costs escalate quickly.

"How bad is the damage?" is a question that has felt like a Kafkaesque nightmare for me over the past 10 days. One can't see any meaningful damage to my car in photos at the scene - though there was obvious damage to the front of the car that rear-ended me. Careful non-expert inspection of my car reveals only a small cosmetic mark to the bumper... which, owing to the age and condition of my car is of no concern to me... If it was my free choice, I'd definitely not try to repair the visible damage. I have been wary that there may be damage behind my bumper - stuff that can't be seen from the outside. I wanted a professional inspection - and, if I was told the damage was only what I can see - then I'd have been happy with zero further action. For the first week, I was told the damage was "repairable" - and that I'd be contacted about the next step soon. I was contacted repeatedly - but about solicitors and making personal injury claims... despite me having been perfectly clear that there were no injuries and I can't even be sure there's any substantial damage to my car. There was also a big push to get me to accept a hire car (as a benefit of my insurance policy - which I have repeatedly declined... because I don't need it).

After a week, I'd been set-up to visit a vehicle repairer for a proper assessment of any damage - and I took my car to them. When I arrived, I was surprised to hear that they would not inspect under the car or behind the bumper (what was required and discussed ad-nauseam with the insurer) and the appointment was over after only taking a few photos [providing no credibly useful new information]. When I got home, I was told that it had been an error by the insurer to book the appointment for me, with the repairer, as my insurer had decided my car would be a (category N) write off... despite no assessment finding credible evidence of any significant damage. I was asked to provide photos of the whole car... and, while I was getting these taken, I received a valuation - just below £3k. I sent the photos anyway... and said I wanted to know what the buy-back price would be.

Ry.Clarke said:

You missed out there. Should have bought it back and pocketed the difference. The value in the car is shot either way:

I know you're responding to someone else's write-off offer... but your comment also applies to my car... but, perhaps, not for the same reasons. My car's done ~135K miles... and the bodywork, in general, is tatty. I had a quote for £1,250 to fix rust patches... though, after I accepted the quote - after a few hours delay, the body-shop told me they no-longer had capacity to start the work (which, I suppose, might be lucky for me.) I've done all the services and kept on top of mechanical maintenance... it's got 4 good tyres; a newish battery; good breaks; suspension components replaced etc. If I had to value the car before the incident - I'd have said it's worth £4K+ to me... but I'd be surprised if I could have sold it to anyone else for over £2k.

I had been thinking about replacing my car for a while - but without feeling any urgency. If I could find a car I want to buy... then writing off (without buying back) would be optimum. If I hadn't been rear-ended, I'd have intended to keep driving my tatty car (perhaps after getting rust treated) for 6-12 months while I look for a deal on a replacement.

I'm thinking about a buy-back... but I'm not sure it will be sensible... as (I'm informed) I will not be given information about a buy-back price until I've accepted the valuation. Given the debacle so-far, I feel as if the buy-back price could exceed the valuation... which would be a bad outcome. Perhaps more realistic is that the buy-back price would be the same as the valuation... which would also be bad... as now (with a cat-N label) I'd expect its trade in value to have diminished to a few hundred quid.

(It's been a very frustrating process so-far. Is it normal that one has to accept a valuation - then be over-a-barrel concerning a buy-back price?)

[aSteve]

Robertb said:

Adblue and diesel engines add an extra layer of complexity and maintenance cost, and the fuel is more expensive.

Modern turbocharged petrol cars seem to offer much of the advantages ie torque and economy, but then these days have also got things like GPFs which can be problematic.

I can t comment on VAG adblue systems but the one in my CLS 350d hasn t so far caused a problem, touch wood.

I comprehend the extra layer of complexity and maintenance costs. A mate has owned a 2015 2.0 adblue Audi A4 for about 7 years... he was charged £3k when the adblue system required attention - making him very anti-adblue now. I do wonder if he was unlucky. His diesel Audi had slightly better power numbers (as spec on paper) than my VW - but didn't feel it had as much urgency when driven. Perhaps it is a heavier car, or - perhaps - adblue and/or other emissions malarkey hamper it. He tells me that his diesel Audi gets about 45mpg (I get about 56mpg from my comparably large VW). He also has a 2.0 petrol A4... which is quicker... but only gets ~40mpg.

The on-paper spec of a (190) 2.0 diesel Arteon suggests 55mpg average and 61mpg on long runs... but the on-paper spec of the 2.0 petrol Arteon only claims 38mpg - which feels like a big difference - both in fuel economy and range.

I assumed Audi and VW diesel engines (of similar age) would, essentially, be the same?

Edited by aSteve on Thursday 9th October 09:16

[NDA]

I would probably try to find a petrol engine - I had a diesel/ad blue in the fleet some while ago. Apart from diesels not being suitable (I am told) for short journeys, the ad blue thing is an additional layer of complexity. I am not entirely sure that any mpg advantage is worth the hassle.

[119]

Ran a couple of adblue cars and never had an issue, well, apart from one of the injectors failing and replaced under warranty early on.

And topping up the tank every few thousand miles. Can’t remember how many as it just pinged up telling me to top it up.

If you are doing a few longish journeys a diesel is a no brainer imo.

[rcspeirs]

I ran a 2019 diesel Skoda Superb estate (DSG) for five years. Traded it in at 137,000 miles. Never had any problems - but the car regularly did long motorway journeys, and rarely did stop-start city journeys. Averaged 50 to 55mpg. Needed to top up the adblue every 8,000 miles or so. A fiddly process from a plactic bottle but once I discovered a service station with an adblue pump that nuisance went away.
Now running a 2024 diesel Skoda Superb estate (DSG).

[geeks]

I could have missed it in that long post. What’s your annual mileage?

[cerb4.5lee]

119 said:

Ran a couple of adblue cars and never had an issue, well, apart from one of the injectors failing and replaced under warranty early on.

And topping up the tank every few thousand miles. Can t remember how many as it just pinged up telling me to top it up.

If you are doing a few longish journeys a diesel is a no brainer imo.

We've never had an issue with adblue either(touchwood). Did over a 100k miles in the 2017 GLC350d, and over 80k miles in the 2022 GLE400d as well. Plus we're currently on 20k miles in the 2024 X5 40d too, and they all have adblue.

Diesel has worked for us for long journeys since back in 2006 now, and it all started with the 2006 E90 330d back then.

[OutInTheShed]

Trying to buy 'for the next ten years' is looking a long way over the horizon IMHO.

I reckon there will be more ULEZ's and so on then. Maybe ZEZ's will become an issue in that time frame?

I've heard hugely mixed reports of the real-life economy of various cars.
Some people seem to find mild hybrids are very good on fuel, others disagree!

A couple of extended family members have PHEV 'repmobiles' which are never plugged in, but seem to give good economy just on petrol.

It's a difficult question because the market price tends to reflect a lot of these factors.


Personally I believe there is only one good reason for paying £20k for a car, and that's because you really want it that badly.
Buying something you don't really like due to some kind of logical argument is just wrong at that price.

I haven't kept up with market prices this year, but I'd be asking myself could I get something for £10k to serve me for 5 years or even £5k to do for 3 years?
Things are changing fast, this year's £20k car could lose a lot of value quickly as shed drivers throw in the towel and buy EVs.

But Adblue?
A diesel that isn't euro 6 doesn't have a long future.

[aSteve]

geeks said:

I could have missed it in that long post. What s your annual mileage?

This is very difficult to answer looking forward. Between 2013 and 2025, my car's done 90,000 mile - so I've averaged about 7,500 miles a year - some years much more; some years much less. I find value in having a car that would be good if (at a moment's notice) something were to change and I needed to do 20,000+ a year - and find it a bonus if I don't need to do that.

[cerb4.5lee]

aSteve said:

geeks said:

I could have missed it in that long post. What s your annual mileage?

This is very difficult to answer looking forward. Between 2013 and 2025, my car's done 90,000 mile - so I've averaged about 7,500 miles a year - some years much more; some years much less. I find value in having a car that would be good if (at a moment's notice) something were to change and I needed to do 20,000+ a year - and find it a bonus if I don't need to do that.

At your general annual mileage, I'd go petrol instead of diesel to be honest.

[anyoldcardave]

OutInTheShed said:

Trying to buy 'for the next ten years' is looking a long way over the horizon IMHO.

I reckon there will be more ULEZ's and so on then. Maybe ZEZ's will become an issue in that time frame?

I've heard hugely mixed reports of the real-life economy of various cars.
Some people seem to find mild hybrids are very good on fuel, others disagree!

A couple of extended family members have PHEV 'repmobiles' which are never plugged in, but seem to give good economy just on petrol.

It's a difficult question because the market price tends to reflect a lot of these factors.


Personally I believe there is only one good reason for paying £20k for a car, and that's because you really want it that badly.
Buying something you don't really like due to some kind of logical argument is just wrong at that price.

I haven't kept up with market prices this year, but I'd be asking myself could I get something for £10k to serve me for 5 years or even £5k to do for 3 years?
Things are changing fast, this year's £20k car could lose a lot of value quickly as shed drivers throw in the towel and buy EVs.

But Adblue?
A diesel that isn't euro 6 doesn't have a long future.

My London commuter is a 2007 C220d, ULEZ compliant, and I disagree with your last comment, I buy every decent diesel I can, when the ULEZ came in and people panicked I made a very healthy living from Diesel cars, and people travelled hundreds of miles to buy them.

To answer the Adblue question, a lot of problems are caused by running it low and air getting in, leaks and poor sealing caps can also cause issues, the ste crystalises very quickly.

Adblue is not a condition of a Euro 6 diesel, there are those without it, and so many have had a delete once issues start because they can be a mare or very expensive to fix, but that is a whole other debate lol.

[aSteve]

OutInTheShed said:

Trying to buy 'for the next ten years' is looking a long way over the horizon IMHO.

I reckon there will be more ULEZ's and so on then. Maybe ZEZ's will become an issue in that time frame?

Neither of the cars at my house are ULEZ compliant - but I've only had to pay the charge once, to date, so ULEZ has not been an issue for me. I agree that such annoying schemes may expand. I live with the uncertainty that I don't know where I may need to travel (perhaps every day) next month. Being ULEZ compliant would be a positive - but (in all probability) is only a relatively small advantage to me.

OutInTheShed said:

Personally I believe there is only one good reason for paying £20k for a car, and that's because you really want it that badly.
Buying something you don't really like due to some kind of logical argument is just wrong at that price.

Today, I can't find any car with a £20k budget that I'd justify by my desire for that particular car. In 2012, that had been the justification for my Passatt-CC after seeing big £15,000 price stickers on 2 Passatt-CCs at a VW garage, and next-door... Aston Marting garage with two cars with similar-font £150,000 price stickers. It immediately struck me that - if I'd "made it" in life, people would expect me to buy one of the Astons... but, for me, I'd prefer one of the VWs. I wasn't looking to change my car at the time - but when my Toyota threatened electrical unreliability... I knew exactly what I wanted to shop for. Test drives let me know that I wanted the 170 model (with DSG, not manual) - so the going rate would be higher than the models that initially piqued my interest.

I do want a car that is larger than a Golf Estate (more comfortable for longer journeys); I do want good range and I do want a pleasant interior. I do want better acceleration potential than the Golf's 1.6 diesel... and, am a complete convert to automatic (DSG type) gearboxes. If getting that costs me £20k - then that's the price I have to pay.

I understand the argument that it may be more cost effective to buy 2 or 3 cars in succession, lasting 5 or 3 years each - rather than one car to last a decade... but I'd prefer to go to the effort of selecting once - then not think about replacing it for a long time. I don't have to borrow to pay for my next car... so there isn't as strong a 'time-value' argument for the purchase price(s) in my circumstances.

OutInTheShed said:

I haven't kept up with market prices this year, but I'd be asking myself could I get something for £10k to serve me for 5 years or even £5k to do for 3 years?
Things are changing fast, this year's £20k car could lose a lot of value quickly as shed drivers throw in the towel and buy EVs.

But Adblue?
A diesel that isn't euro 6 doesn't have a long future.

My (very positive) diesel experiences are all with pre-adblue cars... but, now, in the age range I'm considering, everything is ad-blue. When I say my budget is £20k - I don't need to spend it all. I do want value-for-money... and that's very difficult to gauge. Perhaps I'm just tired of looking at adverts... but... it seems the £20k-ish bracket (~7 years old) offers poor value.... because, a £25k-ish budget (~4 to 5 years old) and a £30k-ish budget (~1 years old) suggest the vehicles I'm looking to buy have had very slow depreciation. On the other hand... I don't really want to be leaving a car for which I've paid £25k+ on a random car-park - and I'd prefer a car few would be motivated to steal. I also feel sure Murphy's law would dictate that my nearly new car would depreciate, in future, far more quickly than ~7 year old cars have depreciated to date.

On the other hand... if I were to go for a 'bangernomics' solution... despite my cat-N car being tatty and old... It's a known quantity (to me) and I've more confidence it can be kept running, without big expenses, than I would have for another old car I might buy from someone else. All my life I've worked on the principle that brand new cars offer poor value (no depreciation yet; relatively high likelihood of manufacturing defects being a problem).... and that one is gambling buying a cheap old car... but that 3 to 4 years old represents a sweet-spot... where there are great quality (proven) cars, with a ~60% discount on MRRP for those who shop around. My problem - right now - is that I'm not finding such gems. With what seem, to me, to be premium prices... I want to make really sure I don't buy a car that turns out to be a "lemon" (i.e. one that lands me with huge bills if I want to keep it running).

anyoldcardave said:

Adblue is not a condition of a Euro 6 diesel, there are those without it, and so many have had a delete once issues start because they can be a mare or very expensive to fix, but that is a whole other debate lol.

Thanks for your advice about how to minimise adblue woes... if I buy a car requiring it.

In my mind, with a target of (ideally) buying at about 4 years old (and a strong dislike for the prospect of owning any hybrid or electric car) I felt my only options would be a petrol or diesel-with-adblue.

I freely admit I don't know any details about Euro-6... but I'd have believed someone if they told me it mandated emissions controls such as adblue. If this isn't the case... I'd be interested to discover examples of diesel Euro-6 cars which do not require adblue... how old a car would I have to accept? I've heard about adblue-delete "being a thing" - but it doesn't appeal to me. I would want my my "dependable, reliable" to be unmodified factory spec.

Edited by aSteve on Thursday 9th October 18:39

[anyoldcardave]

aSteve said:

Thanks for your advice about how to minimise adblue woes... if I buy a car requiring it.

In my mind, with a target of (ideally) buying at about 4 years old (and a strong dislike for the prospect of owning any hybrid or electric car) I felt my only options would be a petrol or diesel-with-adblue.

I freely admit I don't know any details about Euro-6... but I'd have believed someone if they told me it mandated emissions controls such as adblue. If this isn't the case... I'd be interested to discover examples of diesel Euro-6 cars which do not require adblue... how old a car would I have to accept? I've heard about adblue-delete "being a thing" - but it doesn't appeal to me. I would want my my "dependable, reliable" to be unmodified factory spec.

Edited by aSteve on Thursday 9th October 18:39

Most have eventually gone the Adblue route and off the top of my head Isuzu Dmax is the only new one I can think of.

BMW 5 Series from 63 plate on are Euro 6 with no adblue, but it seems 3 Series are not, there is a lot of nonsense out there lol.

We have bought Sprinters from a Major fleet that have come out with Adblue delete, I doubt the major company or the drivers had a clue but the fleet operator was making life easier.

To me it is a simple equation, Adblue and DPF issues can cause MOT failures, done properly, deletes do not, make of that what you will lol.

In my experience for cars and vans, Mercedes Adblue is the most problematic and the turbo can fook your DPF more often than others, but that is only my experience, others disagree or have got lucky.

A 2007 Daf 32 tonner I had years ago had Adblue, so been around for years, everyone of them had Adblue delete, they were Euro 5, until Vosa cottoned on and started plugging in, cue a lot of work reversing them, it could happen with cars too.