DPF regeneration

[Mitchthecabbie]

my 12 plate superb 1.6 diesel    has about 240 000 miles on it now,   its DPF warning light goes on whenever the fuel level  gets low.  usually filling it up and driving it fast for a bit fixes it,  but I think the time has come to do something more longer lasting,  is a Regeneration/cleaning by a garage worth the money?   I am not keen on spending lots as the cars done almost a quarter million miles.  

 

[Ootohere]

Well done on the mileage.

Cheapest option would seem to be do not let the tank go low.

[Mitchthecabbie]

LOL  yup,  I reckon your not wrong.  

 

[jafo]

@Mitchthecabbie

 

Install VAG DPF (free) app and you'll see what is going on with the DPF. 

[Kizotina]

Is a Regeneration/cleaning by a garage worth the money? 

[tuningmania]

To " @Kizotina " - I think - there is no categorically right answer for the cleaning of "DPF". There are few different types of cleaning - with chemicals, with high temperature and mey be another. I do not know, someone, to clear the "DPF" and to forget the problems with it. Every cleaning for me, is short time problem resolving. I Hope to be wrong..

[kitkat72]

I've noticed lately that when my car is on its regen and am sat stationary at traffic light for a while if I pull away hard I am leaving behind clouds of blue smoke!! Only when am on regen it's burning oil any other time it's fine! 

 

It's covered 160k miles oil is changed every 10k religious not had (don't want) the omissions update! Am guessing this is just normal behaviour due to the mileage anyone else experiencing the same?

[langers2k]

@kitkat72 I can't say I've ever noticed any smoke from my CR140 no matter how I drive or if a regen is taking place.

 

It's on 178k with oil changes every 18-20k and doesn't need topping up between services.

[PipH]

17 minutes ago, kitkat72 said:

I've noticed lately that when my car is on its regen and am sat stationary at traffic light for a while if I pull away hard I am leaving behind clouds of blue smoke!! Only when am on regen it's burning oil any other time it's fine! 

 

It's covered 160k miles oil is changed every 10k religious not had (don't want) the omissions update! Am guessing this is just normal behaviour due to the mileage anyone else experiencing the same?

Both myself & wife have/ had Passats with the CBAB 140 CR engine & both exhibited the symptoms you describe above.

My wifes Passat has 125k & my old Passat had 185k on the clocks.

 

Out on the open road or motorway, no smoke at all when regenerating.

 

I have since changed my car for a Superb Estate which has a CFFB 140 CR engine & has 195k on the clock.

This car hasn't shown any sign of smoke while regenerating at all.

 

None of the cars have required any oil adding between services, so I think the blue smoke is probably from the extra diesel injected by the ECU to aid the regen process.

Perhaps the amount added is a bit too much & causes the smoke. 

Maybee it could be trimmed back with VCDS if I knew what parameter to change.

 

So I don't think there is anything for you to worry about.

 

 

 

 

[langers2k]

I believe unburnt diesel should show as black smoke?

 

Blue definitely suggests oil. There might be small amounts collecting in the DPF that are being burnt during the regen. It's this that leaves oil ash and will eventually block the DPF up.

 

Is the car using oil between services?

[VRS_White_Hatch]

On ‎14‎/‎08‎/‎2019 at 20:19, Kizotina said:

I have checked it at local garage,DPF is at 36 g. 

 

 

I bet it needs a bonnet bra, that's a fine stat.

[chimaera]

Normally unburned diesel will come out as white smoke; partially burned diesel comes out as soot/black smoke. Blue smoke is usually lubricating oil.

 

That  being said, a DPF could upend that wisdom depending on what's happening inside it.

[Mitchthecabbie]

Well I fixed my DPF.   

                 After it got to the point that it was constantly re-genning,  I gave in and went to Halfords and paid £85 for their cleaning service.      That was £85 wasted, they couldn't clean it and told me it was 96% clogged.  For just another £380 they would rebuild it for me however..       
 
 So having walked away from Halfords  I went and visited my friend at four-paw racing.     figuring we had nothing to lose we decided on a radical step.  we took the DPF off,  Carefully cut the ends off, taking care to keep to the lines of the original welds, then when the interior  was exposed  we power washed the matrix inside.   for about 30 minutes  water went in  one end and came out  the other  tea coloured with the occasional chunk of cinder.        Eventually the water  came through without discoloration and so we then used and airline to blow dry the matrix.    When this was done we welded the unit back together using the original seams so as to avoid the think looking chopped about.  then re-installed it in the car.    Ran the programmed diagnostic/DPF  regen   and success!  the DPF registered as completely clean with no soot or blockage.   I have since put another 2000  on the car and its not re-generated once, plus the fuel economy has risen by about ten mpg and I have not had one issue with oil pressure either...         All in all this cost a damm sight less than a Halfords rebuild or a replacement and hopefully has bought my old lady (249000 miles  on it now) another hundred K or more  of driving.    

[kitkat72]

7 hours ago, langers2k said:

 

 

Is the car using oil between services?

As far as I know no BUT am not really checking my oil by the dipstick as it's being changed every 10 weeks but I don't have any warning lights or messages telling me oil low.

7 hours ago, PipH said:

 

 

None of the cars have required any oil adding between services, so I think the blue smoke is probably from the extra diesel injected by the ECU to aid the regen process.

Perhaps the amount added is a bit too much & causes the smoke. 

 

 

 

 

 

This is what my own mechanic believes is happing!

 

Forgot to say it's the 2.0ltr 170bhp version 

[superbdreams]

15 hours ago, Mitchthecabbie said:

taking care to keep to the lines of the original welds, then when the interior  was exposed 

would love to see pictures of the internals and your fix if you took any?

[silver1011]

22 hours ago, kitkat72 said:

I've noticed lately that when my car is on its regen and am sat stationary at traffic light for a while if I pull away hard I am leaving behind clouds of blue smoke!! Only when am on regen it's burning oil any other time it's fine! 

 

It's covered 160k miles oil is changed every 10k religious not had (don't want) the omissions update! Am guessing this is just normal behaviour due to the mileage anyone else experiencing the same?

 

This is a sure sign you have engine oil finding it's way into the DPF, quite common.

 

The oil just sits there, until the car performs a regeneration of the DPF, and then under the intense heat the oil is burnt off. Under normal driving it is difficult to see, however when idling at traffic lights the smoke builds up in the exhaust chambers and back box so that when you increase the engine revs to set off the accumulated smoke is expelled all at once. This is what you see in your rear view mirror.

 

If your engine oil levels are not dropping then it isn't anything to worry about, chances are the seals in the turbo are slightly worn and weeping very small amounts of oil past and into the exhaust and DPF.

 

As mentioned above, white smoke is more worrying, this would suggest unburnt fuel. A bit of blue smoke during a DPF regen isn't anything to get overly concerned about, unless you see it with increased regularity, or for prolonged periods after setting off from the traffic lights (suggesting the amount of oil making its way into the DPF has increased).

[silver1011]

17 hours ago, Mitchthecabbie said:

Ran the programmed diagnostic/DPF  regen   and success!  the DPF registered as completely clean with no soot or blockage.   I have since put another 2000  on the car and its not re-generated once, plus the fuel economy has risen by about ten mpg and I have not had one issue with oil pressure either...         All in all this cost a damm sight less than a Halfords rebuild or a replacement and hopefully has bought my old lady (249000 miles  on it now) another hundred K or more  of driving.    

 

Great news, however be aware that the fix might be temporary.

 

By washing out the DPF with high pressure water whilst removing the ash stored within the DPF you've also washed off a lot of the cordierite or silicon carbide coatings within the DPF's baffles that are needed for the regeneration process.

 

At 240,000 miles you've done very well, and the DPF has reached it's expected life span, so anything you do now to prolong that is a bonus. Fingers crossed it gives you many more thousands of miles of uninterrupted service, just know that the DPF's performance is no longer what it once was.

[Mitchthecabbie]

Yes I know there will be some degradation in the filters, but  if I can get another 50k-100k out of it then its been a worthwhile exercise.   I  think it will last at least that long,  and by then the car will have 300k on it and I will have probably retired it.      

[Mitchthecabbie]

2 hours ago, superbdreams said:

would love to see pictures of the internals and your fix if you took any?

Sorry, I didn't take any 😞       but I can describe the internals--a  mesh like filter matrix that is about 8 inches deep.  this sits in the centre of the dpf.   there is a second filter at one end,  which we didn't touch, while the other end is just a steel dome with an outlet.                             The ends are seam welded to the centre.   When we cut ours we followed the seam, and when we  re-welded it, we welded along the seam.        The intention we had when welding it along the seams is that a  few people remove their DPF  and reprogram their car to function without it which is illegal and an mot fail.  I didn't want my one looking like it had been tampered with lest it be mistakenly thought that I had done this.  so  we took great pains to restore its outward appearance back to normal. 

[PipH]

Many moons ago ( 2003 ) I bought a Citroen C5 with the 2.2 Hdi Diesel engine & 150k on the clock.

This was one of the first cars to be fitted with a DPF & had known anything about DPF's then, I probably wouldn't have bought it.

 

Fairly soon after purchase the car started going into Limp Mode with reduced power. ( Probably the reason it was sold )

After some diagnostics I realised it was due to the DPF failing to regenerate.

 

Citroen had designed the DPF so that it could be removed & had deemed that it should be removed every 75k to be sent back to France for cleaning & a service replacement DPF re-fitted at great expense to the owner.

 

I wasn't too keen on the expense part, so decided to remove it myself & jet wash it out.

 

As it had been designed to be removed it was an easy job.

 

I soaked it in a bucket of detergent then jet washed it out thoroughly.

 

The car never had any DPF problems after that for the year that I had it.