DPF cleaners.

[Hugh]

Greetings,

Apologies for not being motorcycle related, there are so many DPF cleaner products on offer but do any of them actually work

One of my sons has a Volvo V70 D5 estate which was fine when he was travelling up and down the motorways each week but now he is only driving very local slow speed mileage which results in his having problems with the DPF. I wonder if any of you good folks have got a recommendation towards a particular additive to try which might clean the injectors plus the DPF unit without removal. We know that he will have to give the car a motorway blast more regularly but an additive might just help to clear the DPF of the current build up.

TTFN

Hugh.

[byewayrider]

He has no real way out... Dpf filters block from carbon dust and the regeneration cycle just burns it off... There are lots of magic potions most don't work... He is better giving the car a good 10mile trash with engine oil hot at 60mph I 3rd gear.... His injectors blocking is another thing also his egr valve will be chocked up too... Long term he is better selling car for a petrol...

Or planning a weekly visit to the country via a motorway..

The new renault Dpf and egr stuff is formula one designed and really is cutting edge.


Also ask on volvo Facebook group or forum..

[soho]

I've just had DPF troubles with the Red malfunction dash light giving the first warning. Ran a diagnostic scanner programme and it showed up as an exhaust temperature sensor failing inside the DPF. Replaced it (not cheap at £170 & it took a set of stillsons to remove the old one) ,but that's a whole lot better than a grand + for a new system !
Scanner cost 40quid, but it pin pointed the problem and also shows the DPF still only 30% full of particles !

Maybe worth some diagnostics first to be sure of the problem ?

[byewayrider]

Yep short journeys don't get engine hot enough to trigger the regen cycle all depends where the sensor is.. As in soho it's the Dpf filter core...

If you removed it the Dpf that is its a auto mot failure but the blocking or disabling the egr valve isn't.. But they work in different ways... Gotta love technology.... Gimme a old Perkins any day.

[catcitrus]

I actually worked for Perkins--and then CAT research in the US--largely on DPFs. They are like a honeycomb with alternate ends blocked. They are a thin wall ceramic which is porous and about 25 micron pore size--but irregular. Some are catalysed directly, some have the additive automatically added in the fuel tank via a dosing system--but the idea is the same--the catalyst essentially allows the carbon trapped in the pores to oxidise at about 450C instead of the normal 600 C. However, the core needs TO GET TO 450C for a reasonable period--and periodically. This doesn't happen with short and cool journeys. Carbon build up causes the backpressure and temperature to rise--if it gets too high with loads of trapped carbon then a thermal runaway can occur melting the DPF. Ash will EVENTUALLY clog the DPF, but meanwhile it needs the higher temps for a period as I said above. Unless a catalyst(cheap) is developed that will reduce the oxidation temperature of carbon further then there is only one solution. Some engines will go into a deliberate late injection mode to deliberately heat up the exhaust gases--but I'm out of touch to know whether this is employed to any extent on passenger cars.

[HarveyCamm]

My Mrs had a Peugeot 807 which had an additive tank (not ad blue) to help with the re-gen but after a few years the computer was regularly saying the the dpf was blocked, needless to say the dealers only wanted to replace at ££££'s

Being a bit 'constricted of pocket' I took the dpf off the car (6 bolts) and flushed it with the hosepipe into a bucket to catch anything, got about a pound of reddish dust particles out of it, dried it off and re-fitted - ran like a charm after that.
Just my experience - not professional advice

[bowber]

We tried dpf cleaner in a minibus filter, it didn't work and we eventually bought an aftermarket one for a fraction of the oem cost, it worked fine for another 2 years when we sold it.

Steve

[catcitrus]

Reverse flushing could help if the dust was loose--the reddish tinge is interesting as I believe Peugeot use an iron based catalyst thats inserted like a rod into a special compartment in the fuel tank and it dissolves at its base and is injected into the fuel based on how many litres of fuel you add at each fill up (more electronics!)----the red dust could have been the residue from the iron based catalyst?

[Richard Simpson Mark II]

As said...modern diesel cars are not suitable for pottering about on short journeys.

I don't know if any of the pour-in products work. You can buy electronic tools that enable you to force a 'hot' regen if the car won't do it on its own.

A very important, and often misunderstood point is that using the wrong engine oil will quickly clog the DPF with metallic ash that cannot be removed with thermally. Modern oil has a lot more than oil in it, and one of the things it contains is zinc dialkyldithiophosphate (aka ZDDP). This is designed to decompose at higher engine temperatures and its components form an anti-wear coating on components such as cams. The coating is wiped off by rockers etc, and then reforms.

And there's the problem. All engines have residual oil on the bore, left by the descending piston, which gets burned in the combustion stroke. The metallic elements in ZDDP are caught in the exhaust stream then accumulate as ash on the ceramic filter. Eventually they partially fill the filter, leaving little room for soot and causing a massive increase in backpressure! Unlike soot, they don't burn.

Engine manufacturers now specify what are called Low or Mid SAPS (sulphated ash, phosphate and sulphur) oils, which contain less ZDDP and more of other non-metallic anti-wear additives for DPF-equipped engines. If these oils are used, the ash doesn't build up so fast, but many garages and car owners don't understand this and use the 'wrong' oil.

If you are interested (someone must be) there's an article in the December 2020 Transport Engineer that you can download here

http://www.transportengineer.org.uk/tra ... -magazine/

Can't think who wrote it...

[Thedktor]

My lad's 2.0 tdi Astra would occasionally do a regen, basically it pumps extra fuel into the exhaust to burn off the soot. You know its doing it cos it smells and the fan runs.

He bought some Halfords stuff which everyone "on the internet" swears works - it is designed to lower the combustion point of the soot. I was very sceptical but it does appear to work!

He did take it for a blast up the motorway in 4th which undoubtedly helped but has been fine since.

I think later engines say 2014/15 on burn much cleaner so don't clog up the DPF so easily, pre that engine technology was not quite good enough and the DPF was kind of a cover-up of sooty engines. Just my theory