DPF Filter Cleaning Concerns DPF filters are required to be cleaned at least once a year. Filters are inspected during the pre-cleaning, cleaning, and post cleaning process. Engines in poor condition will generate more soot from ineffective combustion of oil and fuel. Oil consumption is the major contribution to the need to clean the filter. Regenerating the soot will burn off the fuel-and-oil soot leaving ash. The filter is cleaned for ash not soot. An engine in poor condition will produce more fuel-and-oil generated soot (incomplete burning). Proper service and maintenance can prevent this needless and wasteful condition. Follow the manufacturer’s recommendations and procedures. Monitor the liquids in the engine. Recommendations: FIRST - Snap test vehicle before and after cleaning the filter SECOND -Regenerate filter before cleaning Check engine and exhaust indicator lights

Inlet - Engine side Concerns – soot indicates engine or regeneration concerns. Engine – soot is created by incomplete combustion. The engine is running at a low efficiency level. Repair the condition. Regeneration – soot is regenerated by the DPF. Check the regeneration cycles. Check the vehicle’s application. Exhaust heat is required for regeneration.

Outlet – Tail pipe side Filter can be cleaned and serviced. Follow the manufacturer’s cleaning and servicing recommendation. Concerns: Fuel (higher consumption) – lower mileage indicates engine service concerns. Oil consumption increases cleaning and regeneration requirement Coolant consumption in the engine will destroy the filter.

Outlet – Tail pipe side

FILTER IS DEFECTIVE Filter cannot be cleaned if there was visible smoke on the pre-cleaning snap test. Filter is defective and passing soot. It is against the law to reuse defective filter.

Snap test before cleaning Good performing diesel engines produce very little to no visible exhaust smoke. Modern diesel engines that have over 10% visible diesel exhaust smoke have a service or maintenance concern. Repairing the engine will increase mileage, increase performance, and reduce unwanted diesel exhaust pollution. Bring the engine to operating temperature before perform a pre-cleaning service snap test. Do not regenerate before doing the pre-cleaning service snap test. This will test the vehicle in its normal operating condition. There should be little to no diesel exhaust smoke and none on a diesel equipped with a diesel particulate trap (DPF required on 2007 and newer). The DPF needs to be inspected for failure if there is visual signs of diesel exhaust smoke (5% or greater) during the pre-cleaning service snap test. A regeneration procedure will improve the visual inspection and evaluation of the DPF. This should be done after the pre-cleaning service snap test. This will allow a visual inspection and evaluation of the regeneration process. A passive system (e.g. Cleaire Longview) does not have a manual regeneration. Therefore, it would be required to run the vehicle a distance of 40 miles at freeway speeds to get the exhaust hot enough to regenerate the DPF. An active system (e.g. Cleaire Horizon) would have to be plugged into a regeneration station for the required time. Follow the manufacturer’s regenerations directions. Check the indicator lights to evaluate the regeneration faults, requirements, and successful procedures.

Additionally, some manufactures have computer-base diagnostics to aid and enhance evaluation of the diesel exhaust system. Check with the manufacturer for diagnostic tools and procedures.

Indicator and Warning Lights Indicator and warning lights are essential. These lights communicate indispensible information to the driver and maintenance. It is vital to understand and to act upon the information. Failure to react or to perform the necessary procedure will result in failure of the system and destroy the engine. Build up of soot in the diesel particulate filter (DPF) will signal a regeneration requirement by the differential pressure sensor (DPS), commonly connected to each end of the DPF. The driver may seldom see the indicator lights or react to them depending on the heat of the exhaust. However as conditions change, the heat of the exhaust will change and the driver will need to take the necessary actions to build up the exhaust heat that is vital to regenerate the DPF. Regeneration is the burning off of the unwanted soot trapped in the DPF. Commonly there are two or more temperature sensors. The temperature sensors send a signal to the aftertreatment system to add more fuel to the exhaust to increase the exhaust temperature. If unwanted fuel is present, from an engine in poor condition, a melt-down of the filter can occur. Do not regenerate systems that show overloading of fuel in the exhaust. The DPF will plug with soot without regeneration. Good running engines will produce more exhaust heat than an engine in poor condition. More active regeneration cycles or a more aggressive load will be needed to maintain the exhaust heat as the engine’s performance and condition is lowered. Service and/or repair the engine is required to bring the aftertreatment’s system back to the engineered standards. Good running engines are more efficient and they produce less diesel exhaust pollutants. Not all systems are the same and therefore not all lights are the same. Not all systems use the same levels of communication. It is essential to know where the indicator and warning lights are; and know what they are communicating. Below are examples of new dash lights.

Check Engine Light

Condition requires change. Some systems it indicates service

Stop Engine Light

Stop the engine Tow the vehicle in for critical service

HEST Light

High Exhaust System Temperature Active regeneration May require condition change

DPF Light

DPF requires regeneration Active regeneration occurring

Diesel Exhaust Fluid

Low

Immediate attention required. Check and repair

MIL Light

Malfunction Indicator Light Service and/or repair required for the exhaust aftertreatment system.

Other systems use other methods of communication. It is vital to the operation of the system for the driver and maintenance to understand the communication and to act upon it.

Econix System

Exhaust pipe inspection Clean tailpipe or diverter (DPF tailpipe) is an indication of a good system. Soot in the tailpipe is an indication that the DPF (diesel particulate filter) is not working. Soot is trapped on the engine side of the DPF. The filter will regenerate when the trapped soot on the engine side reaches a determined level and the exhaust is within a desired heat range. Diesel’s operating exhaust temperature affects the DPF’s regeneration process. The diesel’s exhaust is dependent on the engine’s load. Light loads, stop and go, and low road speed will all contribute to low diesel exhaust temperature. A manual regeneration or changing the vehicle’s operation may be required to raise the diesel’s exhaust to a high enough level that regeneration will occur. A defective diesel exhaust aftertreatment system will also prevent regeneration. Careful inspection of the aftertreatment system can identify defective systems. In addition, a poorly performing engine will not burn the fuel effectively. This can increase the regeneration cycles or overload the aftertreatment system because a poorly performing engine will have lower exhaust temperatures. Low exhaust temperature will prevent regeneration. Good service and maintenance will keep the systems working. A poorly running engine or defective systems will produce needless and unwanted pollution and low fuel mileage. A defective or overloaded aftertreatment system can destroy the engine.

A clean tailpipe is an indication of a good aftertreatment system. A good running diesel with a DPF will not have soot at the tailpipe. Tailpipe soot is an indication of a defective aftertreatment system.

This soot is a concern. Soot in an engine with a DPF is an indication of a failed system or service concerns. Snap test the engine. Repair the system if there is visible signs of diesel exhaust smoke (5% or greater). Systems with DPF do not smoke unless there is a failure.

Color change of the exhaust pipe (golden or blued) is a concern of overheating. Check the system. Check the engine for mileage and performance. Unwanted fuel (oil or diesel) will create an uncontrolled regeneration that can destroy the system. Check and repair as necessary.

Soot or soot leaching down the exhaust pipe is an indication of a failed DPF system. DO NOT FORCE THE REGENERATION. Melt down and complete destruction of the system can occur. Disassemble for manual cleaning of the DPF. Make the required repairs before return to service.

Cleaning of the Diesel Particulate Filter (DPF) or Trap Cleaning the DPF is done by special equipment. The materials removed from the DPF should be considered hazardous waste unless it is documented not to be. Manufacturers of the specialized DPF cleaning equipment and machines will have strict documentation procedures for: filter pre-cleaning inspection, cleaning procedures, and post-cleaning inspection. Not all DPF cleaning equipment will meet the legal requirements. Evaluate all the procedures. Question any procedures that do not appear to be responsible in cleaning of the DPF or the containment of the materials removed during cleaning. Track and dispose of materials removed from the filter. Handle all materials with the proper safety procedures. Consider all materials as hazardous waste. Pre-cleaning evaluation of the DPF and exhaust treatment system should include an accelerator snap test before removing or servicing the filter. Visible diesel exhaust smoke is an indication of a failed system. Carefully do a visual inspect the filter for failure. Soot on the tailpipe side of the filter is a common indicator of a failed filter. It is illegal to reuse defective filter. Carefully inspect because not all defects are readily visible. Internal filter defects by not show up in a visual inspection but may all soot to pass through the filter. Visible diesel exhaust smoke passing filter during a pre-cleaning accelerator snap test is an indication of a failed filter.

Diesel exhaust smoke indicates a failed DPF. Snap check before and after cleaning the filter. If the DPF smokes then it is broke.

If the DPF fails a snap acceleration test do a visual inspection of the filter. Carefully examine the filter for cracks. Soot on the tailpipe side is an indication of a failed filter.

Specialized DPF cleaning equipment is used to clean the filter and to contain the material removed from the filter. The filter is cleaned for ash and not soot. Soot is an indication of failed regeneration of the DPF or of an engine that is in need of repairs.

Visual inspection of the diesels exhaust for smoke is critical part of a good inspection procedure. A pre-cleaning- accelerator-snap and a post-cleaning accelerator-snap will help to visually identify that the diesel engine’s exhaust is running clean and the DPF is working. Visible diesel exhaust smoke is an indication of a failed DPF. The engine may need service or repairs before servicing or replacing the DPF. The following are concerns:

Roding the filter – Do not insert a rod into the filter tube cavity. Running a rod into the filter can cause internal damage to the filter by: unnaturally compacting material into the bottom of the filter tube, and/or removing the catalytic coating on the filter, and/or puncturing the filter’s wall.

Steam cleaning or using other liquids can cause the filter to cement close. The closing or restricting the opening of the diesel’s exhaust will cause an increase in unwanted heat content in the combustion chamber. This will result in major and irreversible engine damage. Do not use liquids to clean the DPF.

Special equipment and procedures are used to cook a filter. Cooking a DPF filter can cause damage if the filter has been cemented. The cement will expand puncturing or rupturing the DPF filter. Cementing that is formed inside the filter tubes can cause hidden ruptures and destroy the filter when it is cooked. Cooking a filter to burn off excessive soot or wet soot can help the filter to regenerate. However, there is a concern that temperatures can be excessive. Excessive temperatures will damage the filter beyond repair. Visual inspect the filter after cleaning. Diesel exhaust smoke during an accelerator snap test indicates a failed DPF.

Cracks on a filter may be visible or hidden. Cracked and damaged filter will pass a flow test. A flow test should not be the only indicator of a clean filter. Ultra low flow test numbers indicate that filter is damaged and a careful visual inspection is required. A post-cleaning accelerator snap test is part of the visual inspection. If there is diesel exhaust smoke during an accelerator snap test indicates a failed DPF. Replace the filter