Dpf cleaners are they any good?

[kitkat72]

Hi all

Just started noticing that my superb is doing more regeneration lately as I am now at 50k miles! It's a 2014 64 plate (private hire taxi) had the car from new and only use shell diesel full tank of vpower & half fill with normal shell diesel!

I do boot it now and again for a clear out ???? oil change every 10k!! am now thinking of adding a dpf additive to help prolong the life of the dpf as I know anything above 100k I'll be expecting the dpf problems as my last car (seat exeo) got to 120k before I had the dpf removed ????

So now am trying the best I can to get the most life out of my dpf by using good fuel ????

Dpf cleaners any good or just marketing ploy?

Or is there nothing can be done for the inevitable that's it's going to happen no matter what I try?

Cheere

[chimaera]

The DPF is a wear component, much like the other parts of the exhaust catalyst. What kills them over time is a build-up of oil ash in the filter. A small amount of engine oil combustion is inevitable in a turbo engine so there will be ash residues from this reaching the DPF. You can minimise this by ensuring you use a good 507.00 oil: this spec was specifically formulated to produce low levels of ash in order to protect the DPF.

 

If you're seeing more frequent regens, it could be due to build-up of ash, or it could point to combustion issues in the engine itself. It would be good to get the measuring blocks for DPF loading checked using VCDS or similar. Either way, it might be good to start budgeting for a DPF replacement.

[psycholist]

Another possibility is that one of the pressure sensors on the DPF is giving spurious readings. This is what happened to my car last year. Similar symptoms in that the car started running regens regularly, when I had literally never noticed it doing a forced regen before - my normal use of the car is to drive 100 ish km each time the engine is started, so about as ideal as it gets for long DPF life. I'm past 200 000 km on the original DPF with a remap for nearly 2 years at this stage.

 

As for fuel I run it on whatever fuel is cheapest on the roads I drive - since the legal requirements for the composition of diesel are pretty strict already, if the engine can't run reliably on normal diesel then it's not fit for purpose (And we'd see a hell of a lot more people complaining about their engines dying). I suspect the premium fuel evangelists are quoting a few edge cases and a lot of placebo effect to justify paying over the odds for fuel. Even if the claimed extra mileage for a tank is true it's still cheaper per mile in most cases not to pay the premium. I buy all my fuel on credit card so I have a record of where it came from in case I get contaminated fuel, but I've never noticed diesel from a particular supplier changing the way the car runs.

[DEL80Y]

 but I've never noticed diesel from a particular supplier changing the way the car runs.

My C Class Merc 220 remapped to a 250 is very sensitive on fuel especially if the wife puts in Morrisons cheap stuff the engine sounds like a tractor. There is a lot of talk over on MBClub that they have the same problem so much so that I  run BP only in my cars and Millers EcoMax  in the Merc.

Blurb....

• Increases Cetane rating of diesel by 4 numbers. Engine smoothness, noise reduction and fuel savings confirmed by users.

I also run Fuelly and have seen no difference on running BP  Ultimate even running 5 tanks back to back..

On the taxi system I am on we have got guys with Superb 2's  pushing 250,000 and have had no DPF failures on them.

​Quality oil is the key and also Italian tune up now and then.

How often are you finding it Regens mines is about every 500.

And when I do realise its "regening" I take it for a blast held in 3rd up and down the expressways 

Edited 7 November, 2016 by DEL80Y

[psycholist]

If the cetane is higher then this is a measurable change in the combustion performance of the fuel. Higher cetane is a genuine reason to buy one fuel over another if you're chasing the best possible power output. Did it behave the same way before remapping or was it only after the remap that cheap fuel affected the engine? I'm wondering whether the remap has tuned the car for higher cetane values. Getting 250 bhp from a 220D engine is pretty impressive .

[chimaera]

If the remap has advanced the timing a lot then higher cetane will help, especially with keeping soot down.

[octyal]

It's worth getting it plugged in and checked. I know on the Focus (I think) there is a pipe that runs from the DPF to one of the pressure sensors that can split, causing a false reading and thus giving DPF errors and regens that aren't needed.

[GLIDN]

I have used Liqui Moly Diesel Purge,

 

But also their DPF cleaning kit. You remove a sensor from the exhaust and spray it into the DPF. It cleans out all the build up.

It may prolong the life of your current DPF?

[skippy41]

With the oncoming cold nights, is it best to keep the engine running, to help keep the dpf from cloging up in the first place

[DEL80Y]

 Did it behave the same way before remapping or was it only after the remap that cheap fuel affected the engine? I'm wondering whether the remap has tuned the car for higher cetane values. Getting 250 bhp from a 220D engine is pretty impressive .

 

It was the same before and after remap which went from C220(170bhp) to C250(210bhp).

The C220 and C250 are the exact same engine just different maps.

Just forty extra horses but difference was well improved drivability :clap:

[psycholist]

If the remap has advanced the timing a lot then higher cetane will help, especially with keeping soot down.

Interesting that increasing cetane can lower soot, though is this soot at a given power output or soot in general? If both fuels make the same amount of soot when you floor it and the higher cetane fuel makes slightly more power it may not matter unless the car is making a lot of soot while at cruising engine loads. The injection timing being a smidgen advanced in the C220 engine is a plausible explanation for the characteristics changing with fuel. It's possible that Mercedes design for premium fuel.

 

This is a plausible reason that a higher cetane fuel can be claimed to increase the DPF life. If the engine isn't being run at full power, it won't make very much soot in the first place though, so it might not matter unless the car is driven hard, but the argument is there that after say 5 years, the same engine driven the same way will have a cleaner DPF if it's been on high cetane fuel.

[chimaera]

Interesting that increasing cetane can lower soot, though is this soot at a given power output or soot in general? If both fuels make the same amount of soot when you floor it and the higher cetane fuel makes slightly more power it may not matter unless the car is making a lot of soot while at cruising engine loads. The injection timing being a smidgen advanced in the C220 engine is a plausible explanation for the characteristics changing with fuel. It's possible that Mercedes design for premium fuel.

 

This is a plausible reason that a higher cetane fuel can be claimed to increase the DPF life. If the engine isn't being run at full power, it won't make very much soot in the first place though, so it might not matter unless the car is driven hard, but the argument is there that after say 5 years, the same engine driven the same way will have a cleaner DPF if it's been on high cetane fuel.

 

Cetane is a measure of ignition quality: basically how quickly the fuel will ignite. Higher cetane fuel will ignite earlier in the engine cycle and so it'll have more time to burn before it needs to be sent out the exhaust. Soot is generated due to incomplete combustion, so if you can give more time for combustion then you can reduce soot somewhat.

 

In remaps, it's not unusual to see timing advanced quite a lot to widen the injection band since it's a cheap way to push more fuel through the engine (the expensive way is to fit larger injector nozzles). Having fuel that lights faster here gets your initial injection of fuel lit up quickly and keeps the burn going better through the combustion phase. It may also help if start of injection happens at a less than ideal point in the compression stroke, though you're at risk of bending rods there so a good tuner will avoid doing that.

[kitkat72]

How often are you finding it Regens mines is about every 500.

And when I do realise its "regening" I take it for a blast held in 3rd up and down the expressways

I think it's about twice a week just now roughly 1000 miles a week I do when before it to was once every other week!

There defo a huge problem for us taxi drivers every driver has had some sort of dpf issue most ether get it cut out & remap or get rid of the car! Am just wondering if these additive actually help probably try a terraclean when I've reached 100k????

[DEL80Y]

I think it's about twice a week just now roughly 1000 miles a week I do when before it to was once every other week!

There defo a huge problem for us taxi drivers every driver has had some sort of dpf issue most ether get it cut out & remap or get rid of the car! Am just wondering if these additive actually help probably try a terraclean when I've reached 100k????

Every 500 is about average.

We have had a lot of EGR valves failing but not a single DPF fail in all the Superbs and no fails even with the Seat Toledos which are getting up to 350,000.

Plenty of fails with the old Berlingos :thumbdown: .

As for Terraclean you decide  http://www.briskoda.net/forums/topic/358123-terraclean-huge-problems-monte-carlo-tdi/

Edited 8 November, 2016 by DEL80Y

[TheRobinK]

I think it's about twice a week just now roughly 1000 miles a week I do when before it to was once every other week!

 

 

Hmm - has the type of driving you do changed - as in, proportionately more city driving than cruising?

 

I ask because, AFAIK, our VAG diesels have both active and passive regeneration modes - more stop/start city driving and/or "DPF unfriendly" driving will trigger active regens, which are the ones we notice. We dont tend to notice the passive ones that take care of things when the engine is loaded during motorway driving and has hot exhaust gas on tap.

 

Just as an FYI - there is an interesting article on VAG engines and the DPF here (bookmarked it before I bought my car!): http://www.myturbodiesel.com/wiki/tdi-dpf-faq-repair-cleaning-and-pictures/

[kitkat72]

Hmm - has the type of driving you do changed - as in, proportionately more city driving than cruising?

 

I ask because, AFAIK, our VAG diesels have both active and passive regeneration modes - more stop/start city driving and/or "DPF unfriendly" driving will trigger active regens, which are the ones we notice. We dont tend to notice the passive ones that take care of things when the engine is loaded during motorway driving and has hot exhaust gas on tap.

 

Just as an FYI - there is an interesting article on VAG engines and the DPF here (bookmarked it before I bought my car!): http://www.myturbodiesel.com/wiki/tdi-dpf-faq-repair-cleaning-and-pictures/

 

No the driving I do has not changed if anything since August it should be better as I have an out of town school run so the car gets a good motorway drive for 15 mins this is when I notice it doing a regen if I drive a steady 60/65mph as soon as I come to a stop the car is on a regen! came back on this afternoon when I was doing the school run I left the car ticking over (10 mins) as it was on regen mode came out of the school & the junction was busy booted it to get out looked in my rear view mirror to see a plume of blue smoke!  

 

I just hope this was unburnt oil or something as the car was in regen mode but I tried the same hard acceleration in 1st gear and it was ok then the car went back to normal idle! I got some Wynn's DPF Diesel Cleaner see if that helps

[DEL80Y]

Letting the car tick over on regen is letting the exhaust temp drop to below what it needs..
Next time do as I do and take it for a blast down the expressway..

Is the mechanic defo using good quality low ash oil?

Edited 8 November, 2016 by DEL80Y

[kitkat72]

My mechanic is using 507.00 oil long life! I change it every 10k religious & I frequently do a Italian tune up!

[psycholist]

It sounds a lot more like a DPF pressure sensor than DPF issue then. See what the diagnostics say anyway. Mine gave an intermittent 'unexpected value' type fault IIRC. From what I can gather the reason mine had no warning lights on while the fault was present and it was regenning for no reason was because the spurious pressure value was plausible but indicated a blocked DPF, but gave a warning light without any symptoms when the engine was running correctly because the pressure reading was too implausible for the ECU to believe so it ignored it and ran correctly.

Edited 9 November, 2016 by psycholist