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Ultrasonic DPF Cleaning

Diesel particulate filters from cars, vans, utes, trucks, buses, tractors, and construction plant. Cleaned, tested, returned.

What a DPF does – and what goes wrong.

A diesel particulate filter (DPF) traps the soot particles your diesel engine produces. The system is designed to burn that soot off automatically when the engine runs hot enough. That's the regen burn.

The trouble is, on New Zealand roads – short runs, stop-start traffic, light loads – many engines never get hot enough. The soot accumulates. The filter blocks. The dashboard warning light comes on, the engine drops into reduced-power mode, and you're losing fuel economy long before that.

Once the engine's own regen can't clear it, the filter has to come out. From there, you've basically got three choices.

Three options when a filter blocks.

And one of them isn't really an option at all.

Option 1

Replace

The dealer's preferred answer. $4–5k+ for the part on a working truck. Whole muffler boxes can be a lot more – and on some Volvos, the box is sealed and you're replacing the lot.

Option 2 · Recommended

Ultrasonic clean

Send us the filter. We clean it. You refit. Documented flow pressure proof both ends. A small fraction of replacement cost.

See the process →
Option 3

Delete the system

A workshop remaps the computer to ignore the filter. Cheap now – but it hits the truck's resale value, emissions testing is coming to COF, and deleted vehicles will fail.

The Process

What happens to your filter when it arrives.

  1. Flow pressure test (blocked state)

    Filter goes on our test bench. Air pressure is measured through it in its blocked state. Reading recorded. This is the baseline that proves what was wrong with it when we got it.

  2. Pre-soak in heated detergent

    Filter goes into heated water with detergent. It sits there for up to two hours, depending on what we're seeing. The pre-soak loosens the looser carbon and starts breaking down the asphalt-y residue you get from modern fuel.

  3. Ultrasonic tank

    1–2 hours in the ultrasonic bath at temperature. Tiny bubbles form in every part of the filter and burst, generating localised heat. That heat releases the carbon and ash that's stuck to the tube walls.

  4. Rinse, dry, retest

    Thorough rinse to remove the detergent and the dislodged material. Full dry – we never send a part back with water in it. Then the flow pressure test runs again. The cleaned reading goes on your invoice next to the blocked reading. That's your proof.

What we clean.

DPFs

The diesel particulate filter itself – ceramic honeycomb, varies by vehicle.

Catalytic converters

The cat – sits in the same muffler box. Same accumulation problem.

If it runs on diesel and has emissions gear, we can clean it. Our ultrasonic tanks also clean EGR valves, oil coolers, radiators, and carburettors – not just filters.

For mechanics: what to send, what to expect.

Just the filters (preferred)

If the muffler box dismantles, send just the DPF (and cat if relevant). Lighter to courier, faster to process, lower cost.

Most modern vehicles (10 years or newer) – box dismantles, filters come out cleanly.

Whole muffler box

If the box can't be dismantled (some Volvos, some big bus units), send the whole assembly. We work with what arrives.

Heavier units may need freight rather than standard courier – talk to us first.

Before you take it off

  • Test the oxygen sensor first. A faulty sensor gives the engine computer false readings – the engine over-fuels, and that excess fuel ends up as soot in the DPF. Symptoms look identical to a blocked filter.
  • If the muffler box dismantles, dismantle it before shipping. Saves on freight and turnaround.
  • Use our online booking form so we've got the truck details and the brand. The more we log, the better our pattern data.

Full first-time detail for workshops →

Turnaround and pricing

Standard

2 day turnaround

If a part arrives 10am Tuesday, we'll have a courier on the way back to you Thursday. Standard for most DPFs and cat converters.

from $450 + GST

Express

Overnight where possible

Part in by mid-morning, back on a courier the next morning. Subject to current workload – talk to us before assuming.

POA

Standard pricing covers pre-soak, ultrasonic clean, rinse, dry, both flow pressure tests, and documentation. Non-standard units (whole muffler boxes, sealed assemblies) are quoted individually.

The flow pressure proof.

Every job comes back with two flow pressure readings on the invoice – blocked state in, cleaned state out. Here's what that looks like.

DAF truck DPF

Returned to service.

Scania DPF

Three pressure-cleaning attempts had failed. Cleaned successfully.

Invoice example

The before/after readings printed on the invoice – the proof your customer takes away.

Send us your filter.

Use the booking form to log the job. We'll confirm pricing and turnaround before you courier it.

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