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How to Take Care of Diesel Particulate Filters (DPFs)

What they are

In short, they’re very expensive filters.

Since January 1, 2007, diesel particulate filters (DPFs) are a federal requirement to reduce pollution from all new trucks. 

They are installed in the exhaust stream, and consist of two chambers...

  • The first traps the NO gas and converts part of it to NO2, which is much less harmful to the environment.
  • The second chamber burns the soot that’s caught, leaving a small amount of ash in the filter. Over time, theash builds up and reduces the filter’s effectiveness.

How they affect you

While very helpful to the environment, DPFs cost thousands of dollars.

Further, if you do not maintain yours carefully, the DPF will have a shorter lifespan and a bad core thus resulting in unscheduled downtime that can cost as much as $5,000.

Therefore, maintaining them should be a priority.  

How to maintain them

DPFs need to be cleaned regularly, and the cleaning intervals depend on the application and make.

The general recommendation is as follows...

Diesel Particulate Filters (DPFs)
Recommended Maintenance Intervals for popular Makes and Models

Note: These recommendations do not account for idle time. Idling for long periods of time are harmful to DPFs, since most are passively cleaned while the truck is moving. Make sure to manually regen when prompted by the warning dash-light.

Make Models Highway Application Severe Service
International MaxxForce 5,7, DT, 9-13 250,000 mi / 6,500 hrs 75,000 mi / 2,240 hrs
Detroit Diesel DD13, DD15, DD16 300,000 mi / 9,000 hrs 60,000 mi / 2,000 hrs
Caterpillar C-15, C-13, C-9, C-7 150,000 mi / 4,500 hrs 80,000 mi / 2,400 hrs
Cummins ISB, ISC, ISL, ISM, ISX 200,000 mi / 6,500 hrs 75,000 mi / 2,420 hrs
Isuzu 4HK1-TC, 6KH1-TC 150,000 mi / 4,500 hrs
Hino J05D-TF, J08E-TV, J08E-TW 200,000 mi / 6,500 hrs
PACCAR PX-8, PX-6 200,000 mi / 6,500 hrs
MACK MP7, MP8, MP9 400,000 mi 250,000 mi / 4,500 hrs
Volvo D11, D12, D13, D16 400,000 mi 250,000 mi / 4,500 hrs
GMC DURAMAX 120,000 mi 1st service, every 100,000 mi after

How do I have them cleaned?

Many dealerships have DPF cleaning machines. Before cleaning, they will inspect and test the DPF. The requirements for a passing DPF are:

  • No chips, gouges, melting or surface cracks
  • No loose ceramic
  • Not oil-soaked
  • The “before” air-flow test must fall into the acceptable range, determined by part #

"Before" airflow test results

  • PASS/Continue – Recommend cleaning through Stage 1.
  • FAIL/Red Tag – Recommend purchasing a new DPF, and the current one is not acceptable as a core. Customer has the option to continue attempting to clean, however.

Stage 1 – Pneumatic Cleaning (“Air Knife”)

DPFs have a honeycomb-like structure, with long cells that run the entire length of the filter. The first level of cleaning blows compressed air through each cell.

The first two minutes of cleaning is another test – there is a quick pass of compressed air over the entire filter. If a cell’s walls are torn or pinched, instead of the air burst blowing ash through to the bottom, it would blow back. If 20 cells or more do this, the DPF is considered bad. If not, the cleaning continues

After this cleaning process, the DPF has another airflow test.

Airflow test results

  • CLEAN/Green Tag – The DPF now tests in the recommended range.
  • PASS/Orange Tag – The DPF is not yet in the recommended range, but shows significant improvement. Stage 2 Cleaning recommended, but the customer has the option to use the DPF.
  • FAIL/Red Tag – The DPF does not show significant improvement. Recommend stopping here and purchasing a new DPF, but the customer has the option to continue attempting to clean.

Here’s a video on the process, shown on the same model that our company uses.

Stage 2 – Thermal Cleaning ("Bake")

The DPF is placed in a specialized kiln, with temperatures of 1112°F. This oxidizes any soot and loosens leftover ash deposits.  After this cleaning, the DPF has a final airflow test.

Thermal Cleaning ("Bake")

DPF State Bake Time
Dry 12 hours
Oil/Fluid Soaked 24 hours
Severely Oil/Fluid Soaked 48 hours

Airflow test results

  • CLEAN/Green Tag – Excellent. The DPF is well in the recommended OEM range.
  • CLEAN/Orange Tag – Good. The DPF is currently in the acceptable range, but will not last as long as a green tagged one.
  • FAIL/Red Tag – Poor. The DPF does not meet OEM recommendations/standards.

Pricing

Below is a table of our current pricing...

Current Pricing

Level Price
Inspection – Bad DPF $95
Stage 1 Cleaning (“Air Knife”) $320
Stage 2 Cleaning (“Bake”) – Dry $520
Stage 2 Cleaning (“Bake”) – Oil/Fluid Soaked $615
Stage 2 Cleaning (“Bake”) – Severe Oil/Fluid Soaked $710

Contact us for more information or to speak with an expert.