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...
|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.
|DPF State||Bake Time|
|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.
Below is a table of our current pricing...
|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.