The dreaded DPF

[Jenks]

I have posed these questions elswere but am posting it here as well, hoping for some answers.


We own a Skoda Superb Elegance 2.0ltr TDI PD with a DPF(diesel particulate filter). I am more than a little confused. I understand that the DPF can become blocked under certain conditions, mainly if the engine and thus the exhaust is running at temperatures to cool to burn off the soot accumulated in the DPF . According to the Manual, should the warning light come on. The car must be driven at 1800-2000 revs in 4th 5th gear for a period of 15 minutes during which time the DPF should regenerate its self. This is where my confusion arises. If the car is being driven in the manner described above surely the engine and the exhaust will be running nearly at its coolest. If the car is doodling in traffic would not the engine and exhaust be running at its hottest? Why is forward speed necessary for regeneration of the DPF? Could not the engine and exhaust temperature be raised to a temperature necessary to burn of the soot with the car stationary after all 2000 revs is 2000 revs whether stationary or moving? Why must the car be moving? Hope someone can help clear my confusion.


Jenks

[Jenks]

sorry couldn't work the change of font size.

[numskull]

Jenks,

How many miles has the car now covered? Have you had the DPF warning light illuminate? If not, stop worrying about it, and just enjoy the car!

Num

[Jenks]

Originally Posted by numskull

Jenks,

How many miles has the car now covered? Have you had the DPF warning light illuminate? If not, stop worrying about it, and just enjoy the car!

Num

numskull..

The car is driven mainly by my partner and she is averaging 100 miles a day. The DPF warning light has only appeared once, ironically about ten minutes after we picked it up from the dealer (ex Demonstrator 2500 on the clock) scared the $hit out of me as you can imagine. I guess I might be coming over as a tad anxious, I'm not really. I just want to learn as much about the potential problem as I can. You can rest assured, we are enjoying the car. I drove it up to Loughborough last week from Winchester, mostly on cruise control set at 70 mph and got 54 mpg. How could I not be pleased. Forgot to mention we have about 8k on the clock now.

Jenks

[SJFISHER67]

My DPF light flashed on once over a year ago. Flashed on then straight off, so kind of ignored it (not appeared since - touch wood).

At the time I did go into my local Skoda dealer, where a mechanic told me over 2500rpm for 10 minutes or more. Since then every now and then I do rev the car or drive it in a gear that maintains the revs over that amount.

[bahnstormer vrs]

I have a DPF on my Octavia vRS TDI; had it now for a year and 18,000 miles. It gets a daily 50 mile commute including a couple of full throttle accelerations up a M-way slip road and M-way cruise.

The regeneration cycle, with its 1,000 rpm tickover and gruff engine note for a few minutes, has happened about 3 or 4 times only and then only after being 'stuck' in urban traffic (NW London where I work gets pretty clogged up at times). I have not had the DPF warning light flash on at all.

That your DPF light came on after leaving the dealer is probably symptomatic of it being trundled around the car park whilst it was in the dealership, and not reflective of its daily use.

Originally Posted by Jenks

The car must be driven at 1800-2000 revs in 4th 5th gear for a period of 15 minutes during which time the DPF should regenerate its self. This is where my confusion arises. If the car is being driven in the manner described above surely the engine and the exhaust will be running nearly at its coolest.

No; engine gas temperature is a function of combustion. as described there is plenty of combustion, so plenty of temperature.

If the car is doodling in traffic would not the engine and exhaust be running at its hottest?

No; less fuel so less combustion, but typically incomplete so generation of soot/particulates.

Why is forward speed necessary for regeneration of the DPF?

To provide good combustion and use plenty of fuel.

Could not the engine and exhaust temperature be raised to a temperature necessary to burn of the soot with the car stationary after all 2000 revs is 2000 revs whether stationary or moving? Why must the car be moving?

Stationary the engine will require little fuel to run at 2000 rpm and therefore not enough to burn off the soot.

Hope someone can help clear my confusion.

Clear or confused further?

[SJFISHER67]

Originally Posted by bahnstormer vrs

I have a DPF on my Octavia vRS TDI; had it now for a year and 18,000 miles. It gets a daily 50 mile commute including a couple of full throttle accelerations up a M-way slip road and M-way cruise.

The regeneration cycle, with its 1,000 rpm tickover and gruff engine note for a few minutes, has happened about 3 or 4 times only and then only after being 'stuck' in urban traffic (NW London where I work gets pretty clogged up at times). i have not had the DPF warning light flash on at all.

That your DPF light came on after leaving the dealer is probably symptomatic of it being trundled around the car park whilst it was in the dealership, and not reflective of its daily use.

To answer some

The 1000rpm tick over has happened a few times to me. I didn't know what that was, so have learnt that today!

I did actually take it to the dealer for something else once, and told them. They said they didnt know why! Restores your faith in dealers doesnt it!

[Jenks]

Originally Posted by bahnstormer vrs

I have a DPF on my Octavia vRS TDI; had it now for a year and 18,000 miles. It gets a daily 50 mile commute including a couple of full throttle accelerations up a M-way slip road and M-way cruise.

The regeneration cycle, with its 1,000 rpm tickover and gruff engine note for a few minutes, has happened about 3 or 4 times only and then only after being 'stuck' in urban traffic (NW London where I work gets pretty clogged up at times). I have not had the DPF warning light flash on at all.

That your DPF light came on after leaving the dealer is probably symptomatic of it being trundled around the car park whilst it was in the dealership, and not reflective of its daily use.


No; engine gas temperature is a function of combustion. as described there is plenty of combustion, so plenty of temperature.




No; less fuel so less combustion, but typically incomplete so generation of soot/particulates. To provide good combustion and use plenty of fuel. Stationary the engine will require little fuel to run at 2000 rpm and therefore not enough to burn off the soot. Clear or confused further?

Great reply.. Many thanks

[rotodiesel]

The Superb is a real VAG masterstroke - it would be difficult to see how they could have mismanaged it more if they had set about trying to kill it.

The original model mix simply didn't address the market (no estate and 3 useless petrol engines) with silly trim enhancements which are just not worth fitting to such an old chassis. To make matters worse, VAG did nothing to correct the inherited Passat design faults (water ingress, front suspension) which are well known in the Trade.

So, the poor old Superb gets relegated to taxi duty as long as it's a diesel. What do they do?

VAG fit the thing with a piece of kit (DPF) which makes it "unsuitable for city driving" according to their literature.

The marketing people ought to be shot. It could have been quite a useful car in basic form with some sensible body variants. As it is, having been already resigned to taxi duty (all Superbs in my locality are taxis) it's now no use even for that.

rotodiesel.

[Supurbia]

Jenks, where did you buy the car from?

[Jenks]

Originally Posted by rotodiesel

The Superb is a real VAG masterstroke - it would be difficult to see how they could have mismanaged it more if they had set about trying to kill it.

The original model mix simply didn't address the market (no estate and 3 useless petrol engines) with silly trim enhancements which are just not worth fitting to such an old chassis. To make matters worse, VAG did nothing to correct the inherited Passat design faults (water ingress, front suspension) which are well known in the Trade.

So, the poor old Superb gets relegated to taxi duty as long as it's a diesel. What do they do?

VAG fit the thing with a piece of kit (DPF) which makes it "unsuitable for city driving" according to their literature.

The marketing people ought to be shot. It could have been quite a useful car in basic form with some sensible body variants. As it is, having been already resigned to taxi duty (all Superbs in my locality are taxis) it's now no use even for that.

rotodiesel.

Crikey mate you appear to have a pretty poor opinion of the Superb . We haven't had ours long enough to form a definite opinion but so far we love it. I admit I am a bit anxious regarding the DPF. Thanks to the expertise of the people who post on this forum at least I now have a better idea of the problems that might arise. Whats the problem with the front suspension and at what sort of mileage is it likely to occur, and is it an expensive fix?



Jenks

[Supurbia]

Ok, I'll rephrase that, is it an 07 Comfort in Blue ?

[rotodiesel]

The front suspension is a crazy set up using 4 links and balljoints per side. It was designed to minimise torque steer, which it does at the expense of imposing impossibly high stresses on the joints and bushes. If you put one of these cars on swivel plates and turn it from lock to lock you will see what I mean.

To make matters 50x worse, the ball pins on the upper arms and trackrods are held in place by unplated pinch bolts. As these are in the wheelarch (the suspension pinchbolts are in line with the tyre) they get pelted with water and mud - and rust in solid.

VAG have a special tool to get them out, which doesn't work. I take all these bolts out once a year and grease them - it's a quick job which can be done without jacking the car up or removing the wheels.

It's an expensive fix when the joints fail as there are so many of them - pattern parts from GSF and the like. I wonder why...

When the bolts are rusted in the cost to fix the problem becomes totally out of proportion to the problem - just because VAG didn't detail the design properly.

I'm happy with my Superb for the purpose for which it was bought (towcar). I am disgusted that VAG have perpetrated all these old Passat design faults (+ a few new ones) when it appeared wearing a Skoda badge. VAG UK have also not been forthcoming with essential information.

So, I won't be buying another VAG vehicle of any kind and due to their hopless mismanagement of the Superb, the residuals are very poor. It's a pity, Skoda have made a good job of screwdrivering it together, the 1.9 is a cracking diesel and the body is galvanised. It's been fairly reliable so far - but not as good as an equivalent Japanese car.

rotodiesel.

[Supurbia]

Originally Posted by rotodiesel

So, I won't be buying another VAG vehicle of any kind and due to their hopless mismanagement of the Superb, the residuals are very poor. It's a pity, Skoda have made a good job of screwdrivering it together, the 1.9 is a cracking diesel and the body is galvanised. It's been fairly reliable so far - but not as good as an equivalent Japanese car.

rotodiesel.

Me too, hopefully in the next two months.

[Jenks]

Originally Posted by rotodiesel

The front suspension is a crazy set up using 4 links and balljoints per side. It was designed to minimise torque steer, which it does at the expense of imposing impossibly high stresses on the joints and bushes. If you put one of these cars on swivel plates and turn it from lock to lock you will see what I mean.

To make matters 50x worse, the ball pins on the upper arms and trackrods are held in place by unplated pinch bolts. As these are in the wheelarch (the suspension pinchbolts are in line with the tyre) they get pelted with water and mud - and rust in solid.

VAG have a special tool to get them out, which doesn't work. I take all these bolts out once a year and grease them - it's a quick job which can be done without jacking the car up or removing the wheels.

It's an expensive fix when the joints fail as there are so many of them - pattern parts from GSF and the like. I wonder why...

When the bolts are rusted in the cost to fix the problem becomes totally out of proportion to the problem - just because VAG didn't detail the design properly.


I'm happy with my Superb for the purpose for which it was bought (towcar). I am disgusted that VAG have perpetrated all these old Passat design faults (+ a few new ones) when it appeared wearing a Skoda badge. VAG UK have also not been forthcoming with essential information.

So, I won't be buying another VAG vehicle of any kind and due to their hopless mismanagement of the Superb, the residuals are very poor. It's a pity, Skoda have made a good job of screwdrivering it together, the 1.9 is a cracking diesel and the body is galvanised. It's been fairly reliable so far - but not as good as an equivalent Japanese car.

rotodiesel.

Oh no! Another sleepless night Thanks for the info forewarned is forearmed.


Jenks

[mikes]

I take all these bolts out once a year and grease them - it's a quick job which can be done without jacking the car up or removing the wheels.

Any chance of posting details/tutorial.

I'm sure many owners would be interested - espacially if it's a DIY job.

Thanks

[Jenks]

Originally Posted by Supurbia

Jenks, where did you buy the car from?

Sorry mate.. We bought the car from Marlboroughs of Isleworth it is a Superb elegance 2.0ltr PD we now have 8000+ on the clock.


Jenks

[rotodiesel]

Haynes manual 4279 for the B5.5 Passat shows the suspension detail reasonably well. All you need is a couple of 16 AF (5/8" AF fits better) spanners.

rotodiesel.

[sidewaze samm]

Originally Posted by rotodiesel

Haynes manual 4279 for the B5.5 Passat shows the suspension detail reasonably well. All you need is a couple of 16 AF (5/8" AF fits better) spanners.

rotodiesel.

Roto
My good lady wife came home from shopping yesterday, complete with a present for me - Haynes manual 3917, for the '96-'00 Passat. Any idea whether this is similar enough or whether the differences mean I need to go to Halfrauds to try and swap it? (or send her back)

cheers

[Lummox]

Just a point worth making the Superb DPF doesnt selfregenrate. The filter has a finite life and will require changing as it doesnt empty out fully.