Today I am driving ... a Nissan Micra 2016

[monkeyhanger]

Your 2005 Audi 2.0TDI didn't have one, unless you had access to a development 170ps unit from Audi's CEO as it wasn't available until late 2006 in any VAG car.

If you are doing short journeys with a DPF, you'll know about it. Doing less than 10 mile journeys on a daily basis, you'll have experienced active regen, making stop-start unavailable, pushing idling revs up 200rpm above the norm, getting abysmal mpg while an active regen is happening, and the smell of burning.

They'll have been even more frequent and prevalent on an early DPF model.

I've had 2 Golf's and 2 Sciroccos with DPF equipped 2.0TDI units and an Audi A1 with a DPF equipped 1.6TDI lump. Driven a few various hire cars with them too (BMW,/Vauxhall/Ford) and they're very noticeable in operation if you're not doing 15+ miles a journey to keep your regens passive.

[Andy Beats]

If you are doing short journeys with a DPF, you'll know about it. Doing less than 10 mile journeys on a daily basis, you'll have experienced active regen, making stop-start unavailable, pushing idling revs up 200rpm above the norm, getting abysmal mpg while an active regen is happening, and the smell of burning.

Yeah, you do know you're getting a regen.
In a BMW you get the 'burning rubber' smell when you get out of the car, it doesn't intrude inside the car, thankfully.
Other cars didn't smell, but you got the raised idle.
I don't agree with the abysmal MPG though.
It might be a bit worse than normal, but not so I noticed particularly, if the MPG plummeted I'd have noticed.
In general though, DPFs aren't the 'scary things' people used to think they were and the factories have them sussed.
As you said earlier too, replacement isn't the £1500 dealer-only thing it used to be, you can get a DPF cleaned out for a couple of hundred max.
Given that it might take you 80K+ miles for the DPF to need cleaning out, it's a negligible cost of well under 0.5p per mile.
Any salesman who still spouts DPF scare stories deserves a slap.

[Leif]

Your 2005 Audi 2.0TDI didn't have one, unless you had access to a development 170ps unit from Audi's CEO as it wasn't available until late 2006 in any VAG car.

If you are doing short journeys with a DPF, you'll know about it. Doing less than 10 mile journeys on a daily basis, you'll have experienced active regen, making stop-start unavailable, pushing idling revs up 200rpm above the norm, getting abysmal mpg while an active regen is happening, and the smell of burning.

They'll have been even more frequent and prevalent on an early DPF model.

I've had 2 Golf's and 2 Sciroccos with DPF equipped 2.0TDI units and an Audi A1 with a DPF equipped 1.6TDI lump. Driven a few various hire cars with them too (BMW,/Vauxhall/Ford) and they're very noticeable in operation if you're not doing 15+ miles a journey to keep your regens passive.

You’ve made some of the points I was going to make. Manufacturers claim the DPF is now fine, and fortunately VW have a reputation for honesty. Sorry, I mean they cannot be trusted. An active regeneration takes ten to fifteen minutes, so if you turn off the engine mid way, it won’t complete, and you’ll eventually get blockage. If you drive for fifteen minutes at 40 mph passive regeneration should occur.

Add on the fact that modern diesels are sophisticated machines and expensive to repair, they are best avoided outside of warranty unless you do longish journeys. That said, I wonder how reliable small turbo petrols are? Ford had serious issues with theirs and did not acknowledge it. The VW units seem okay.

And Andy is again saying his small number of samples is representative of all cars, just as his positive experience of Nissan is contrary to owner surveys.

[monkeyhanger]

.

Add on the fact that modern diesels are sophisticated machines and expensive to repair, they are best avoided outside of warranty unless you do longish journeys. That said, I wonder how reliable small turbo petrols are? Ford had serious issues with theirs and did not acknowledge it. The VW units seem okay.

Modern diesels are sophisticated, but surprisingly robust. You don't hear many stories of in warranty or out of warranty.big issues, unless they're related to someone running a DPF equipped one to do 5 miles a day in.

I've had 7 VWs and an Audi with TDI engines, and the only issues I had were

1. a failed Turbo actuator on a 2003 Polo 1.9 TDI at 5 months old. Replaced and no further bother - my sister bought it off me at 2 years old and ran it for 9 further years before selling it to buy something bigger.

2. My 2007 Golf GT Sport TDI170 PD (what a mouthful!), with the first DPF VAG implemented. Had regen issues initially because VW hadn't ironed out the running software. Once sorted, there were no further running issues.

My Dad has done well in excess of 400k miles over 3 Golf TDIs, without engine issue, half of those with a tuning box - just shows how resilient those units are. Diesel fuel being a lubricant does help the longevity - diesel engines are built to do 250k miles without bother, petrols are not.

Really not confident about a highly strung 1.0 unit lasting 100k miles when they spend half their time running a large proportion of their output. A 2.0 (as in the Golf R) running with a 300ps output is also highly strung but will spend a tiny amount of operational time putting out more than a third of its output.

Ford has been running highly strung small units longer than VW, and at higher outputs - these new taller gears for WLTP compliance may prove to be clutch killers for manual boxes.

Running a VW out of warranty, I'd have more confidence in the TDI.

[Leif]

Regarding diesels, I’m going by advice from the Honest John web site, he gets countless letters and emails each week from car owners, so he knows which engines and cars are more reliable, and what the issues are. It’s not a case of it will go wrong, but it is more likely to go wrong and if they do, then it costs.

Ford actually had a design fault with their small turbo petrols, and refused to acknowledge it for years. Basically the engine can catch fire. Seems to be unrelated to the turbo and small cylinder heads:

https://www.whatcar.com/news/ford-ecobo ... now/n17972
https://inews.co.uk/essentials/lifestyl ... egal-bill/

Small 1 litre engines are reliable, I took my VW Up to 130,000 miles then sold it as I was wary of higher servicing costs, no reason why it can’t do a lot more. Lots of makes now use small petrol engines. The fact that the car is small means there is not so much load on the engine. Engine and turbo longevity will depend more on regular oil changes and the driving style. Some people thrash engines, and other components.

[monkeyhanger]

What was the output on that UP though? I bet it wasn't highly strung like most of the current offerings, tiny engines with big turbos. Was it naturally aspirated, maybe 60ps? It won't have tall gearing to really test the clutch like the new wave of WLTP compliant models We've a few years history of tiny engines with turbos but not with tall gearing in the mix.

The small car argument doesn't apply to the current Polo though - it's almost the same weight as a Golf with the same engine (Polo is only about 40kg lighter) and almost the same size as a Golf. Lots of people reporting smelly clutches here doing pretty much every day things, presumably because of the tall gearing (and/or possibly a weak clutch). Pulling 1300kg with a 1.0 and high gearing is going to make that engine work hard a lot of the time.

Give me a high mileage TDI over a high mileage TSI every time.

Although better than most sites, honest John is still full of people who complain about faults, and no real representation of people without faults (because people just don't send in en masse to tell John their 140ps 1.0 Fiesta is running fine.

I'd be taking those reported faults and putting them into context with the numbers sold to determine comparable marque/engine reliability.

Beyond warranty, you have the uncertainty of whether those cars are being maintained properly when there isn't the requirement to do in order to maintain your warranty.

[Andy Beats]

And Andy is again saying his small number of samples is representative of all cars, just as his positive experience of Nissan is contrary to owner surveys.

How many cars do I have to have experience of?
Surely if DPF faults are as common as your internet searching suggests, I'd have had snags somewhere along the line.
Unless you're suggesting I'm the luckiest man on earth.

[Adam_013]

My Dad has a Volvo S60 D4 (2.0TDi), with a DPF fitted and for the last 3 years has been doing 5 miles to work with the car barely getting warm.

It has a run over 20 miles maybe every 2-3 months. And he's never had an issue as of yet.

Sent from my Pixel 2 XL using Tapatalk

[Andy Beats]

My Dad has a Volvo S60 D4 (2.0TDi), with a DPF fitted and for the last 3 years has been doing 5 miles to work with the car barely getting warm.

It has a run over 20 miles maybe every 2-3 months. And he's never had an issue as of yet.

Neither did I doing 4.5 miles a day, in various cars.
Could be months between long runs too.
Active re-generations are very good these days.

[Leif]

What was the output on that UP though? I bet it wasn't highly strung like most of the current offerings, tiny engines with big turbos. Was it naturally aspirated, maybe 60ps? It won't have tall gearing to really test the clutch like the new wave of WLTP compliant models We've a few years history of tiny engines with turbos but not with tall gearing in the mix.

The small car argument doesn't apply to the current Polo though - it's almost the same weight as a Golf with the same engine (Polo is only about 40kg lighter) and almost the same size as a Golf. Lots of people reporting smelly clutches here doing pretty much every day things, presumably because of the tall gearing (and/or possibly a weak clutch). Pulling 1300kg with a 1.0 and high gearing is going to make that engine work hard a lot of the time.

Give me a high mileage TDI over a high mileage TSI every time.

Although better than most sites, honest John is still full of people who complain about faults, and no real representation of people without faults (because people just don't send in en masse to tell John their 140ps 1.0 Fiesta is running fine.

I'd be taking those reported faults and putting them into context with the numbers sold to determine comparable marque/engine reliability.

Beyond warranty, you have the uncertainty of whether those cars are being maintained properly when there isn't the requirement to do in order to maintain your warranty.

HJ is a decent journalist and very knowledgeable about cars. He has his foibles, but he talks to lots of other journalists, and receives lots of emails etc from people. Yes of course the number of complaints will be greater for cars produced in large numbers, but he’s not daft, he knows which cars sell in bucketloads, and which are rare. And he will see which faults are more common for a given car compared to other similar cars. He noted gear box issues with the VW Up, mine was great, but the user forum also had lots of reports of gearbox issues.

But your last sentence hits the nail on the head, it’s why I don’t ‘save a fortune’ and buy a one year old used car. A car may be built okay, but not serviced properly, or driven badly, hence it breaks after a few years. And anyway you save more more buying new from a broker, or getting a dealer to match a broker. I suppose a new car when the old one reaches 130,000 miles or more is one of my luxuries.

[Leif]

And Andy is again saying his small number of samples is representative of all cars, just as his positive experience of Nissan is contrary to owner surveys.

How many cars do I have to have experience of?
Surely if DPF faults are as common as your internet searching suggests, I'd have had snags somewhere along the line.
Unless you're suggesting I'm the luckiest man on earth.

I’m not saying they are common, it in the past a lot of people have had issues with the DPF due to short journeys. Are the latest DPFs fine? Perhaps. I’ll let others make their own decisions.

As for luck, having a DPF not fail is not my definition of luckiest person on Earth. Winning a million pounds, having good health, marrying a good woman for life etc are better, in my book anyway.

[monkeyhanger]

My Dad has a Volvo S60 D4 (2.0TDi), with a DPF fitted and for the last 3 years has been doing 5 miles to work with the car barely getting warm.

It has a run over 20 miles maybe every 2-3 months. And he's never had an issue as of yet.

Sent from my Pixel 2 XL using Tapatalk

Doesn't it go anywhere on the weekend, perhaps further than 5 miles? Although they're better than they used to be, with the DPF pretty much sat on the exhaust manifold now to get hot as quick as us possible, I'd expect it to be trying to initiate active regens almost every journey.

[Adam_013]

My Dad has a Volvo S60 D4 (2.0TDi), with a DPF fitted and for the last 3 years has been doing 5 miles to work with the car barely getting warm.

It has a run over 20 miles maybe every 2-3 months. And he's never had an issue as of yet.

Sent from my Pixel 2 XL using Tapatalk

Doesn't it go anywhere on the weekend, perhaps further than 5 miles? Although they're better than they used to be, with the DPF pretty much sat on the exhaust manifold now to get hot as quick as us possible, I'd expect it to be trying to initiate active regens almost every journey.

He's recently switched jobs and it's on a 9 mile run now, but until then, rarely used bar the odd run here and there and towing the wobble box 2-3 times a year.

Sent from my Pixel 2 XL using Tapatalk

[monkeyhanger]

My Dad has a Volvo S60 D4 (2.0TDi), with a DPF fitted and for the last 3 years has been doing 5 miles to work with the car barely getting warm.

It has a run over 20 miles maybe every 2-3 months. And he's never had an issue as of yet.

Sent from my Pixel 2 XL using Tapatalk

Doesn't it go anywhere on the weekend, perhaps further than 5 miles? Although they're better than they used to be, with the DPF pretty much sat on the exhaust manifold now to get hot as quick as us possible, I'd expect it to be trying to initiate active regens almost every journey.

He's recently switched jobs and it's on a 9 mile run now, but until then, rarely used bar the odd run here and there and towing the wobble box 2-3 times a year.

Sent from my Pixel 2 XL using Tapatalk

It definitely won't have been working at its best on short runs like that. In my wife's hands, doing 8 miles each way, our A1 1.6TDI 116PS was forever choked up and was lucky to break 40mpg. When we swapped cars (because she needed a 5 door when off on maternity leave), it was like a different car with me doing 20 miles each way to work in it. Even driving it hard it was returning 65mpg.

Perpetually interrupted active regens on short journeys sees diesel (intended for post injection burn to raise the exhaust temp) being dumped in the sump, thinning the oil.

[Leif]

As I understand it the extra diesel dumped 8nto the sump can also raise the sump level which can cause serious problems.