Liqui Moly DPF cleaner

[Greg Roles]

To edit my response above I just heard Western Filter are charging $650 to bake off the DPF, but they no longer need to cut them open, so perhaps they are doing some sort of similar chemical flush / bake now too. I did look at that full on Liquimoly kit, and yeah, it is a comprehensive kit, but still, pricey!

[Ryeman]

Mines still within the warranty period .....it'd be good to know if they put an additive in during the fixed price service period.
Id probably put a dose of the Penrite DPF cleaner in annually.

[Amalgam]

Mines still within the warranty period .....it'd be good to know if they put an additive in during the fixed price service period.
Id probably put a dose of the Penrite DPF cleaner in annually.

I don't think they do as there is no mention of any additive in my last service invoice.

At $25 per bottle and cheaper when on sale, it is cheap insurance.

[Ryeman]

I don't think they do as there is no mention of any additive in my last service invoice.

At $25 per bottle and cheaper when on sale, it is cheap insurance.

Bring on the sales!

[Umai Naa!!]

No additive in the diesels, at dealership level.

Petrol only.

That's the official line, although there may be some dealers out there who'll try and upsell you something.

[Ryeman]

No additive in the diesels, at dealership level.

Petrol only.

That's the official line, although there may be some dealers out there who'll try and upsell you something.

Being on fixed price servicing......not likely I suspect.

[Greg Roles]

Guys,

Just to be clear there are various levels of DPF "cleaners" and processes, and thus the results.

The $20-$40 DPF cleaners you add to the fuel tank or the fuel filter are usually just a can of Toluene or a similar high hydrocarbon solvent, and this will no doubt clean the fuel system, the injectors, and help the DPF both passively, and actively regenerate. If you look at the active ingredients they usually just say something like 770g/L liquid hydrocarbons. They are a great first step, and if your car is having issues doing a normal regen, a great thing to try. Remember a "regen" is burning off the black carbon based soot. They do NOTHING for the grey oil ash that builds up and cannot be routinely burnt off.

Your DPF is slowly building up ash, which eventually renders it "blocked", while routinely storing and burning off the typical black soot over and over. There are two things going on with your DPF. This soot cycle and the capacity between regens drops over time.

The second level of DPF cleaner you add to the fuel tank has CERIUM or a similar catalyst, usually a precious metal, added to it, and these are much harder to find. This is a "proper" cleaner. They cause a regen to happen in no time flat, and this is basically what "add blue" type diesels use in their exhaust treatment. This will drop soot in no time, but again don't do anything for the oil ASH.

The $760 Liquimoly DPF cleaning system mentioned above, is a series of additives put directly into the DPF. They have somehow worked out a way to remove both the soot, and the ash - at least to some extent - as well. How they have done this is currently beyond me, but I'm researching it. The whole point is this system is not just getting the soot levels back down to zero, whilst leaving your ash levels at their current state, it is aiming to drop your DPF back towards new, but I'm still skeptical as to just how much this is possible chemically. Perhaps they achieve huge temps to reduce the ash even further, not sure. I hope to be wrong!



The final, and only really sure way I know of is to backflush the ash back out of the DPF, in the reverse direction to exhaust flow. This is what Western Filter do with their physical DPF cleaning service, and what I've done twice now with a pressure washer. It's a mission, but mainly to get the DPF and pipe out, the washing is pretty simple. I have found however that a backflushed DPF fills up with ash / soot faster than a new one, and you sadly can't beat a new core for efficiency - as you expect. Searching eBay.de or a similar euro eBay site for a low km used DPF is also a good option, I routinely see them at about $700-$1000 Aussie.

So just make sure that when you talk "DPF cleaner" you are comparing apples with apples.

[Greg Roles]

I've just become a bigger fan of Liquimoly, very impressed with their research and development team.

[Ryeman]

You would think that before long, online 'plain label' versions will go a long way to resolving the expense of the 'Brand Power' ones.
One could be cynical and suggest difficulty of 'access' is a nice little earner also.

[Amalgam]

Great write up Greg

( Both articles )