Diesel Particulate Filters (DPF): Clean or Replace?

Diesel particulate filters (DPFs) have been a standard feature in heavy-duty diesel engines since 2007, helping manufacturers meet EPA emissions standards and reduce harmful pollutants. However, every fleet eventually faces a critical question: should you clean or replace a DPF?

A recent article in Fleet Maintenance Magazine, written by Emily Markham, explores this topic in detail. Below, we summarize the key points, including how DPFs work, cleaning strategies, maintenance best practices, and when replacement is necessary.

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How Diesel Particulate Filters Work

DPFs are ceramic filters with thousands of micro-pores designed to trap soot and ash from diesel exhaust, reducing emissions and improving air quality. As a DPF collects particulate matter, it creates backpressure, which must be managed through regeneration and cleaning.

Three Types of DPF Regeneration

1. Passive Regeneration – Occurs naturally when the exhaust reaches a high temperature (around 1,112°F).

2. Active Regeneration – Triggered by the engine control module (ECM) when exhaust temperatures are too low for passive regeneration. The system injects diesel fuel into the exhaust to burn off soot.

3. Forced Regeneration – Manually activated by the driver if soot buildup is excessive and automatic processes fail.

While regeneration removes soot, it does not remove ash, meaning periodic professional cleaning is required.

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DPF Maintenance: Preventive Care & Cleaning Methods

A well-maintained diesel particulate filter should last for the lifetime of the vehicle. However, proper DPF maintenance requires:

• Routine inspections for exhaust leaks, fluid leaks, and sensor malfunctions.

• Hydrocarbon injector maintenance to ensure proper aftertreatment function.

• Scheduled cleaning to remove accumulated ash.

DPF Cleaning Methods

There are multiple DPF cleaning strategies, but not all methods are effective.

1. Pulse Cleaning – Uses bursts of air to dislodge soot and ash.

2. Thermal Cleaning (Baking) – Exposes the DPF to high temperatures to loosen deposits.

3. Liquid Cleaning – Uses chemical solutions to flush out contaminants.

The problem? No industry-wide standard defines a “clean” DPF, leading to misinformation. The Technology & Maintenance Council (TMC) recently introduced RP 374, which outlines best practices for cleaning DPFs and diesel oxidation catalysts (DOCs).

When to Replace a Diesel Particulate Filter

Even with proper maintenance, a DPF will eventually degrade. When cleaning is no longer effective, replacement is the only option.

DPF Replacement Options

1. OEM DPFs – Direct from the vehicle manufacturer, ensuring EPA/CARB compliance but often expensive.

2. Aftermarket DPFs – Less expensive but banned in California due to lower efficiency.

3. Remanufactured DPFs – Cleaned and reused filters, but quality varies, and they are also banned in California.

Choosing a replacement DPF should be based on budget, compliance requirements, and the manufacturer’s recommendations.

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DPF Cleaning vs. Replacement: Making the Right Choice

For most fleets, regular cleaning is the best strategy to:

• Extend filter lifespan

• Improve fuel economy

• Maintain EPA compliance

• Prevent expensive engine repairs

At Enviromotive, we provide industry-leading DPF cleaning equipment, as well as replacement filters, gaskets, clamps, and bungs. Whether you need to clean or replace your DPF, we have the right solution.

📞 Call (800) 954-8265 to discuss your DPF needs with our expert team.