DPF Cleaning: What’s Actually Involved (Step by Step)

You’ve seen the service listed online. Maybe your garage recommended it. But what actually happens during a DPF clean? Is it just a spray and pray, or is there a proper process that makes a real difference?

At DPF Clean, we treat every job with the same methodical, workshop-level approach. Whether it’s an on-car clean or a full off-car refurbishment, the process is built around one goal: restoring flow and performance, with data to prove it.

This guide walks you through our step-by-step DPF cleaning process — so whether you’re a trade garage or a diesel driver, you know exactly what you’re getting.

Step 1 – Vehicle or Filter Inspection

Every job starts with a visual check. If your vehicle is with us, we scan for fault codes, check sensor readings, and inspect the live data to understand soot levels, regeneration history, and back-pressure values.

If it’s a loose filter sent to us by courier, we examine the housing, mounting points, and core for physical damage, cracks, melted substrate, or signs of oil contamination. If we spot a serious fault, we stop and contact you before going further.

Step 2 – Initial Flow Test

Before cleaning begins, we run a pressure test. This tells us how blocked the filter is and whether flow is restricted by soot, ash, or oil residue. You’ll get a “before” reading in millibar (mbar), which we record and compare after the clean.

This test proves how severe the blockage is and sets a baseline for our results.

Step 3 – Choose the Right Clean

We offer two main types of DPF cleaning:

• On-car clean – suitable for partially blocked filters where soot load is under 90%. We use a chemical flush and controlled forced regen via diagnostics.
• Off-car refurbishment – ideal for heavily blocked or ash-loaded filters. We remove and fully clean the DPF using our in-house water-based rig.

If you’re not sure which method is right, we can advise based on live data or test readings.

Step 4 – Off-Car Cleaning Procedure

For full off-car DPF cleaning, we use a workshop-grade rig that pushes heated detergent and water through the filter in both directions. This loosens carbon, dissolves soot, and flushes out ash that simple spray methods can’t reach.

• Filter is soaked with chemical solution to loosen compacted deposits
• Hot water pressure flush clears each cell from both sides
• Compressed air blast dries and forces out final residue
• Clean unit is cooled and prepped for testing

We don’t use ovens, acid dips, or DIY-style sprays. Only manufacturer-grade equipment is used on your filter.

Step 5 – Final Flow Test and Report

Once the DPF is clean, we retest flow using the same method as before. This gives a clear before-and-after comparison in mbar. The results are printed and included with the job — so you can see the difference in real terms.

Our goal is to bring flow back to under 5 mbar — matching or exceeding factory spec. If we can’t achieve that due to internal damage or oil saturation, we’ll discuss replacement options with you directly.

Step 6 – Refit and Road Test (if applicable)

If we’ve removed the DPF in our garage, we now refit it with new gaskets and clamps, clear fault codes, and perform a controlled regen (if needed) using diagnostics. We then road-test the vehicle and confirm that pressure, temp, and soot sensors are behaving as expected.

If the filter was sent in via post, we ship it back using a tracked courier service. Most postal cleans are completed within 2–3 working days of arrival.

Step 7 – Follow-Up and Warranty

We back every clean with a 6-month flow guarantee (Terms & Conditions Apply) — provided the vehicle meets our cleaning requirements. That means no underlying faults (injectors, turbo seals, EGR), and the filter wasn’t physically damaged or blocked beyond 98% when cleaned.

Our terms and conditions explain the Warranty (Terms & Conditions apply) in full. You’ll get paperwork and flow reports to keep on file or show your customer (if you’re a garage).

Why Our Process Works

We’ve cleaned thousands of filters for private drivers, garages, lease companies, and fleets. This process doesn’t guess. It doesn’t hope. It measures, flushes, proves and protects.

We help prevent misdiagnosis, avoid unnecessary replacements, and get cars and vans back on the road — fast.

Need a DPF Cleaned? Here’s What to Do

• Local to Hanley? Drive in and we’ll advise which clean is right
• Removed the DPF already? Use our postal service
• Got fault codes? Bring them in and we’ll read the live data

Call 07827533529 or contact us online to book your DPF clean now.