Octavia Mk3 Diesel VRS Excessive DPF regenerations?

[Auric Goldfinger]

Mines the same, I think it does more regens to keep the DPF clean all the time and not wait until it gets a load of soot in then tries to do a regen

[JungleJames]

This is my first Skoda and could well be the last. The type of driving seems to make no difference to the intervals for regeneration at all. I can do a 20 mile run booting it engine well warmed up and just before you stop it starts a regeneration. You know it's happening as mine begins to run rough almost feeling like it's going to backfire which I assume is the change in fuel mixture. Absolute rubbish.

Sportsbilly, as we are now nicely into winter, your car will regen a lot. Once into next summer, it should eventually calm down.

Anyway, I shall try and put your mind at ease a little. These Mk3s don't seem to be getting any DPF warning lights coming up. Yes they regen a lot when new, and during winter, but they don't seem to be conking out on people. They seem like good reliable DPFs so far.

 

Although, did you mention it starts running rough when doing an active regen? Not sure that sounds right. Don't recall mine doing that. At what speed will it run rough? 30, 40, 50, 70?

 

A couple of things which I have found out. If you stop the car in the middle of a regen, then next time you start her up again, you are best heading onto the motorway for a good run. If however you carry on with stop start journeys for the next few days, then the car will keep trying the regen over the next few days. It may not be regular either, and it'll be more than once, because it probably wont complete it on short hops. Until you next do a good long 70mph drive, you will get irregular attempts at regens. Even if it seems to have completed a regen one day, the chances are it wont have, and the next day it'll start trying again. As I say though, a good run should sort it all out.

 

Also, unfortunately the system is not smart enough to know when is best to do a regen. I once finished a 300 mile run up the motorway, only for the car to start a regen right towards the end once id slowed down. Hence I interrupted it by switching the engine off. Thankfully the next day I was straight back out on the motorway, but had I not been, id have had irregular active regens over the next few days.

 

Going by what you say, there is a chance the car has done just enough on the short hops, so when you head out on a good motorway run, it doesn't bother trying a regen until the end. You then stay in the cycle of active regens every other day.

 

Certainly as mentioned above, the best way I find of clearing it all, is once I interrupt an active regen, head straight out on the motorway next time im in the car and let it complete it.

Unfortunately it is one of those annoying things, but it isn't just Skoda or VW. In fact, Id say you are in the best place, as the VW DPFs seem reliable things. Ive read of some bad ones out there.

[andyvee]

This is my first Skoda and could well be the last. The type of driving seems to make no difference to the intervals for regeneration at all. I can do a 20 mile run booting it engine well warmed up and just before you stop it starts a regeneration. You know it's happening as mine begins to run rough almost feeling like it's going to backfire which I assume is the change in fuel mixture. Absolute rubbish.

20 miles is hardly a long run! If your longest journey is 20 miles why did you buy a diesel?

 

'Booting it' isn't the way to get the regen out of the way either, you will be loading the DPF with more soot!

 

A constant 2200-2500rpm on the motorway with the engine and oil up to temperature is the best way to get it to clear. This may mean you need to drop down to 5th.

[JungleJames]

20 miles is hardly a long run! If your longest journey is 20 miles why did you buy a diesel?

 

'Booting it' isn't the way to get the regen out of the way either, you will be loading the DPF with more soot!

 

A constant 2200-2500rpm on the motorway with the engine and oil up to temperature is the best way to get it to clear. This may mean you need to drop down to 5th.

Adding to what Andy say's. No, 20 miles may not be enough to clear it. Id be looking at 20miles there and 20 miles back, all in one go. Even then, as I said before, it depends when you do this.

But yes, if your longest run normally is 20 miles, then you are going to have to take a few pleasure drives down the motorway.

My reasoning for switching to diesel this time (apart from the fact I had an extremely weird urge to own a diesel!!!) was because I head up from Kent to Scotland at least twice a year, and do a lot of driving up there. If it hadn't of been for those Scottish trips, the chances are a diesel wouldn't have worked for me.

[classic]

This is my first Skoda and could well be the last. The type of driving seems to make no difference to the intervals for regeneration at all. I can do a 20 mile run booting it engine well warmed up and just before you stop it starts a regeneration. You know it's happening as mine begins to run rough almost feeling like it's going to backfire which I assume is the change in fuel mixture. Absolute rubbish.

Sounds like you've got a fault, I would take it to a dealer.

I do 20000+ miles a year and even at that I nearly got a petrol.

In 15000 miles I have noticed the fan staying on twice (1.6tdi but same systems), and occasionaly the stop start saying engine must be running. I wouldn't know it had a dpf if I wasn't interested in cars. If you read about them, as stated by others above, they do regenerate a lot more than earlier models to protect the dpf, for example every 450 miles you'll get a mileage regen regardless of any others that might have recently been triggered by other factors.

Edited 7 December, 2014 by classic

[snala]

Mine is up to 11,000 miles now and gets a noticeable regen about every tank of diesel at some stage. So if its doing it at every 450 miles as classic says above then that is right then.

Is worse in winter as car doesn't get hot enough to burn off naturally, especially on a motorway going 1800 rpm no matter how long you drive. Seems better now as it is always over 20 deg C all the time over here.

Interesting how diesel vs petrol works in different countries though. Over here diesel is < $1.20 a litre (60p) and 98 petrol is at least a $1 more a litre (so £1.20). Diesel VRS is only £350 pounds more than the petrol to buy new.

Last whole tank was 56 mpg and have saved just under £1000 pounds in fuel costs in 8 months compared to the petrol so is the right choice for me regens and all. 

Edited 8 December, 2014 by snala

[classic]

Actually I was wrong in what I put in my last post - there is a mileage regeneration every 465 miles only if there has been no regen or successful regen within the last 465 miles. It is done regardless of the soot loading of the dpf. (must be sober in future before commenting on forums!!).

Either way it's going to attempt a regen at least once per tank of fuel.

Edited 8 December, 2014 by classic

[Sportsbilly]

Just for confirmation 20 miles isn't my longest trip. As I have stated earlier I've done a 140 mile trip loaded car and it's done a regeneration as soon as I've stopped. The fact is its starts a regeneration and I drive it until it's cleared out in auto stop start functions and the fans no longer runs which should mean the regeneration has finished and then as little as 140 miles later it doing another regeneration. Must be a fault surely!!

[andyvee]

If that is the case take it to your dealer as my previous O3 didn't behave like this, and my new one has only done 1 regen that I have been aware of in 1600 miles

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[littleade]

As above I'd suggest you take it to your dealer as you may well have a faulty sensor which is causing your car to regen so often.

[Gabbo]

The DPF system doesn't wait until its 100% full and then continunally force a regeneration until its back to 0%.

In addition, the best conditions for regeneration are not while driving on the highway or driving really hard like many people seem to believe.

 

On the highway the load on the engine is low & the cooling effect of the wind is high.

When driving hard the exhaust temperatures fluctuate greatly so its difficult to safely control the temperatures in the DPF during regeneration.

 

The best conditions are when driving at moderate speeds on A or B-roads which is why most people will see the regeneration start when they come off the highway & are close to home and hence you then see Stop/Start is unavailable & the fan is running when you stop.

 

If a regeneration is interrupted you might have, for example, burned 25% of the soot which takes the loading just below the threshold where a regeneration is required.

In this case on your next drive, it wont attempt a regeneration but after a short distance maybe 100/200km you would exceed the threshold again & another regeneration would be attempted after a seemingly short distance.

Equally, if a regen is required but you drive straight onto the highway, the system may wait until there are more favourable conditions to begin the regeneration, so after a 200km journey the regeneration starts again when you enter a town.

 

 

The fan running when you stop the car is not necessarily the sign of a problem, neither is regenerations occuring close to each other.

Unless the DPF warning light comes on, just drive the car as you normally would.

Edited 12 December, 2014 by Gabbo

[andyvee]

And it all depends how you drive. 'Booting it' as the OP described his driving will load the DPF, and regens won't happen when driving like this either

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[TomLux]

I just drove the first 100km in our new VRS TDI and I had my first regen when getting back home (and it was thus interrupted). I'm glad I read on this forum that the burning smell is normal, but I am surprised about the fact that it's done it already so soon. And I was gentle with it...

[john96]

Both yesterday and today I had the fans on/high idle when I arrived at work after a 20 mile commute, I assume its because of the low temps here at the moment, but when i drove the car about an hour later the idling speed was fine again. My car has done 3000 miles now, and I reckon I have noticed the regen happening more often recently

[Miz]

The DPF will regen after a set mileage (it used to be around 600 miles) regardless of the soot levels.

 

How do you know it's performing a regen if you are doing 70mph?

I think it would be good if there were a "regen active" light to let you know, or even a countdown same as the service/oil change countdowns.

[Dempsek]

Don't forget there is a difference between active and passive regenerations, plus the DPF is viewed as as life of car part.

 

Passive regen the DPF is hot enough to burn the soot without the use of any extra fuel.

 

Active regen adds fuel into the DPF after combustion costing fuel and reducing MPG.

 

Ultimately if your driving style / type is not suited to DPF regenerations it will cost you in diesel / reduced MPG and the lifespan of the car.

 

I had a Fabia Greenline II 1.2TDI that I dove a 75 mile round trip using top gear 5th as much as possible and then made the same trip latter using 4th as the top gear with the second trip being .5MPG less. There are to many variables to say for sure that active and passive regens had an impact on the difference between the two MPGs, but it is my view that the second journey had less if any active regens.

 

Just try modifying your driving a bit by dropping down from top gear on the motorway for part of your journey and in town do not go above 3rd.

[JungleJames]

 

In addition, the best conditions for regeneration are not while driving on the highway or driving really hard like many people seem to believe.

 

On the highway the load on the engine is low & the cooling effect of the wind is high.

When driving hard the exhaust temperatures fluctuate greatly so its difficult to safely control the temperatures in the DPF during regeneration.

 

The best conditions are when driving at moderate speeds on A or B-roads which is why most people will see the regeneration start when they come off the highway & are close to home and hence you then see Stop/Start is unavailable & the fan is running when you stop.

I frequently have my car start a regen on the motorway. Only obvious if it is cold, or if I am stopping as soon as I get off the motorway (ie no a or b road in between).

During the summer, the car seems to prefer regens on the motorway, and I hardly ever notice them. In the winter, its a mixture.

[octavianestate]

Though the DPF system maybe required to meet diesel emission laws i can't help feel it may be a nail in the proverbial coffin for the future of the diesel car (by this i only refer to the car And not other diesel users, haulage, shipping, oil rigs etc)

With diesel being at the higher price over petrol for a number of years now in my opinion the diesel car is the sole market of the corporate fleet world.

unless one has a corporate fuel card it seems to me that the DPF system is ironic. Has the ability to clean up harmful gasses but at the expense of burning more fossil fuel. This would be like running windfarms on a fossil fuel in order to 'create' some green power. Pointles.

Edited 21 February, 2015 by octavianestate

[pipsyp]

Don't forget there is a difference between active and passive regenerations, plus the DPF is viewed as as life of car part.

Passive regen the DPF is hot enough to burn the soot without the use of any extra fuel.

Active regen adds fuel into the DPF after combustion costing fuel and reducing MPG.

Ultimately if your driving style / type is not suited to DPF regenerations it will cost you in diesel / reduced MPG and the lifespan of the car.

I had a Fabia Greenline II 1.2TDI that I dove a 75 mile round trip using top gear 5th as much as possible and then made the same trip latter using 4th as the top gear with the second trip being .5MPG less. There are to many variables to say for sure that active and passive regens had an impact on the difference between the two MPGs, but it is my view that the second journey had less if any active regens.

Just try modifying your driving a bit by dropping down from top gear on the motorway for part of your journey and in town do not go above 3rd.

Not quite true, DPF is a service item (i.e it will eventually fail and have to be replaced) but should last at least 100k miles, considerably more so providing the conditions are right and its allowed to regen when required.

[octavianestate]

Are all manufacturers using a form of DPF tech?

[Gromle]

Are all manufacturers using a form of DPF tech?

I think dpf was made mandatory back in 2009?

[Dempsek]

Not quite true, DPF is a service item (i.e it will eventually fail and have to be replaced) but should last at least 100k miles, considerably more so providing the conditions are right and its allowed to regen when required.

I agree a DPF should last 100,000 miles or more if the driving conditions are optimal for DPF regeneration, it's the cost of replacement.

 

According to the AA DPF replacement is £1000 plus, So a motorway driver could be looking at a new DPF from 4 years on and it might be seen as a reasonable company cost, but when i had a company diesel (pre DPF) the cars were changed at 100,000 to 120,000 miles leaving a potential big bill for the next owner.

 

Jo blogs buys a diesel and only drives 10,000 miles a year under optimal conditions the DPF could need changing at 10 years effectively righting the car off, and at any time less than 10 years the owner could have a bill in excess of £1000.

 

After say 5 years I can see at £500 pound all in to replace a DPF as not too expensive and a serviceable item, but at £1000 plus on a car worth only around £5000 is not a reasonable cost.

[Richf]

My Superb started to do regens on a more and more frequent basis above about 70k , the car was used for a daily commute which involved 25 miles on the motorway but had been used for shorter trips earlier in its life but even then some motorway speed driving was always involved, we also noticed the economy dropping 

 

Until the manufacturers cut the cost of replacement then owners will look at other options come replacement time, they should be serviceable or exchange items at least

 

I'm not a fan of DPF's , I dont feel they are a solution to the issue of diesel particulates more of a sticking plaster fix to get around the rules. The dpf in turn makes the engine less efficient during normal running and  many of the emission savings are lost during a regen when emissions can rise 4 times over normal running, its all a bit of a con and its the owner who has to pay.

 

Perhaps it will get better with time but it seems at present DPF vehicles produce large amounts of nano particles that are actually more harmful than the particles non dpf equipped vehicles make so another alternative will be required or the diesel car will be legislated out of existence

[TomLux]

With diesel being at the higher price over petrol for a number of years now[...]

That's only true for the UK, Bulgaria, Hungary, Romania, Serbia, Sweden and Switzerland, In every other country in Europe Diesel is cheaper than petrol (RON95 and much cheaper than RON98). The reasons for this may be different. Over here diesel is 1,075€/L, RON95 is 1,157 and RON98 is 1,219. In Luxembourg the VRS TDI is only 500€ more than the TSI, yet mpg is much better and on every tank you save 10%.

 

 

I still prefer a good petrol engine, but hey..

[jthyssen]

That's only true for the UK, Bulgaria, Hungary, Romania, Serbia, Sweden and Switzerland, In every other country in Europe Diesel is cheaper than petrol (RON95 and much cheaper than RON98). The reasons for this may be different. Over here diesel is 1,075€/L, RON95 is 1,157 and RON98 is 1,219. In Luxembourg the VRS TDI is only 500€ more than the TSI, yet mpg is much better and on every tank you save 10%.

 

 

I still prefer a good petrol engine, but hey..

 

In Denmark the diesel is cheaper too (about €0.13 per liter), but that is partially offset by a higher yearly road tax (~€500 yearly for the diesel vs ~€85 for the petrol). 

 

Given the higher price for the diesel car you would have to drive a lot of kms for the diesel to be cheaper over, say, 3 years.