No.: 14 TS-24
September 3, 2014

TO:

Service Locations

FROM:

Service Systems Development

SUBJECT:

Guidelines for EPA07 Aftertreatment Cores and Ash Measurement

ISSUE
The purpose of this document is to provide guidance in determining ash levels in DPF filters before
and after alternate cleaning processes are employed. All DPF cores are eligible for full core credit
except units exhibiting damage, defined below. In the event damage is present, cores will be
eligible for a single partial credit amount that is established by DDC and may be evaluated and
revised periodically.
CORE ACCEPTANCE GUIDELINES
Substrate Surface Damage: The DPFs shown below have experienced substrate surface
damage caused by gouges. Any damage to the surface of the substrate (left picture) that is
greater than .125” (3.18 mm) below the substrate surface, .500” (12.7 mm) in length and .251”
(6.38 mm) in width will affect integrity of the substrate. Use the illustration below to clarify
maximum gouge specification. If the edge chips (right picture) extend to a depth that exceeds
.125 in. (3.18 mm) from the outer edge toward the center (being more than three cell rows), the
DPF core is subject to unacceptable core charges.

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Vertical Cracking: Cracks that run laterally through the substrate and can be seen on one or
both sides of the surface. Cracks running symmetrically along the structure or in a webbed
pattern indicate extensive cell damage in the interior of the substrate and are considered
unacceptable.

Horizontal Cracks: If the DPF substrate face has any soot residue around the circumference of
the substrate. Internal horizontal cracks allow soot and ash to pass through the substrate. Soot
evidence, identified with a wipe of a light colored cloth, can be a slight amount of black film
around the edges of the exhaust side to moderate and extreme cases where soot buildup occurs.
All circumstances are considered unacceptable core.

Slight soot film

Moderate soot residue

Extreme soot build

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Foreign Matter: If the DPF cells are restricted (any foreign matter) on the surface of the
substrate, covering an area the size of more than one square inch, then this is considered
unacceptable.

Fusion or Melting: If the substrate has experienced a burn through, where the face of the
substrate may be partially melted or exhibits black splotches of soot, the cell structure has been
converted to molten ceramic due to an uncontrolled thermal event and is considered an
unacceptable core.

Substrate Slippage: Substrate which moves inside the stainless steel can is known as slippage,
caused by unusually high back pressure. Substrates flush or protruding past the can flange that
come into contact with or within ½” (12.7 mm) of sensor or sensor bung are considered
unacceptable.

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Substrate Canning Damage: Any excessive damage to the can and/or the flange of the filter is
also considered unacceptable and internal damage may have resulted. Witness marks from band
clamps are acceptable as long as the worn or rusted area has not penetrated through the can.

Acceptable band clamp marks

Acceptable

Major Dents: Punctures or major dents in the can caused by road hazards, handling, and/or
shipping, are not acceptable. A major dent is defined by any dent that exceeds .500” (12.7mm)
below the surface of the can.

Puncture not acceptable

Major Dent Not acceptable

Dent more than .500” deep

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Bent or damaged mounting brackets are not acceptable.

Not Acceptable
Flange damage is unacceptable when the flange is crimped; however, the illustration of flange
damage on the right is minor and acceptable.

Not Acceptable

Acceptable

NOTE: If any major component of the aftertreatment system is replaced, the root cause of its
failure must be reported. Failure to make necessary repairs may result in a premature failure of
the replacment. Filter cores must be returned in the supplied returnable plastic shipping barrel and
packaged as received.

Ash Measurement and DPF Cleaning: Detroit does not endorse ash measuring and cleaning of
DPFs, but is providing these basic cleaning alternatives for EPA07 filters only. Although Detroit
has not fully evaluated every Diesel Particulate Filter cleaning machine or process on the market,

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data has shown that air cleaning the filter does not consistently achieve a uniform removal of ash
across the filter. Ash left behind from air cleaning results in hot spots within the substrate leading
to cracks allowing unfiltered exhaust to pass through the DPF. The graphic below illustrates the
ash content of an air-cleaned filter.

3D View of Ash Content After Inadequate Cleaning

PROCEDURE
Option A:
Reuse of existing filter with measured ash level that is below an acceptable level as determined
using the measurement procedure detailed in this publication.
Option B: (Recommended)
Replace existing filter with a filter cleaned using Detroit Engines proprietary reliabilt® cleaning
process.
Option C:
Use an aftermarket filter cleaning device to remove ash from the DPF.
NOTICE: All EPA07 filters are the same length (15 inches); when the ash level in the filter reaches
three inches, it is considered full.

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ASH MEASUREMENT PROCEDURE:
TOOLS REQUIRED
• Depth Gauge
– Multipurpose Stainless Steel Wire
– 0.039” diameter x 24” length
– 18.25 AWG gauge
– McMaster-Carr P/N: 8908K75 (pack of 100) or any wire meeting the above
specifications.
NOTE: If wire gauge gets bent, dispose of and replace. If any force is applied to move the
wire in the cell, it will provide a false measurement.
• Measuring Device: Ruler, tape measure, etc.
INSTRUCTIONS
NOTE: A Parked Regeneration must be performed
prior to measurements being taken.
1. Allow filter to cool completely.
2. Set filter on bench with the inlet side facing up.
Identified by an arrow on the side of the DPF can, the
inlet side is the end the arrow points away from. (Fig. 1)

Inlet Side

Fig. 1

Fig. 1
3. Using the wire depth gauge, drop (DO NOT FORCE)
the gauge into 10 randomly selected cells using a
circular pattern. Allow gauge to drop freely (DO NOT
FORCE). (Fig. 2)

Fig. 2
4. Once travel of the wire gauge has ended, slightly tap on the side of the wire depth
gauge using the index finger to verify it has reached maximum depth. (Once again,
DO NOT FORCE the gauge in a downward movement.)

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5. Pinch the wire gauge using the thumb and the
forefinger at the very top edge of the substrate brick
and remove gauge. (Fig. 3)

6. Using a tape measure or other measuring device,
measure the distance from the end of the gauge to
the fingernail of the forefinger to the nearest 1/8” and
record. (Fig. 4)

Fig. 3

Fig. 3

Fig. 4
The table below can be used to estimate how much ash is in a given filter before or after cleaning:
DPF Ash Depth Conversion Chart
Column A
Particulate Filter Length

Column B
Particulate Filter
Measured Depth

Column C
Actual Ash Volume
1.250

Example

15.0

13.750

column A – column B =
column C

Measurement 1
Measurement 2
Measurement 3
Measurement 4
Measurement 5
Measurement 6
Measurement 7
Measurement 8
Measurement 9
Measurement 10
Column C Total
Calculated Average
Calculated average equals column C total divided by 10

If calculated average ash depth is 1.5 inches or less, the filter does not need to be cleaned and
can be reinstalled and the ash accumulator reset.

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If calculated average is greater than 1.5 inches, the filter must be cleaned using either the Detroit
recommended process or an alternate process.
Frequently Asked Questions:
What is a full filter and when does it need cleaning?
Detroit particulate filters are considered “full” when the ash level has reached a predetermined
level in the cells. Refer to the Filter Identification Chart in this document for filter identification and
“Full” filter specifications.
What is a clean filter?
Any filter with less than 0.5 inches of ash is considered a clean filter.
How do I clean the filter?
Presently, the Detroit proprietary reliabilt® cleaning process is the only process that has been
approved by Detroit Diesel Corporation.
A number of alternate cleaning system manufacturers have developed their own processes based
on the designs of their respective cleaning equipment. To help reduce the risk of filter damage
while cleaning, be sure to follow the appropriate cleaning equipment manufacturer's
recommendations for equipment use. Detroit does not assume any liability or risk associated with
the use of non-company-approved cleaning processes.
How do I test the filter to determine if it is clean?
Alternate cleaning methods in the market today have highly variable results and Detroit
recommends checking the ash level in a minimum of 10 cells and averaging the results to
determine amount of ash remaining in the filter. Cells checked should include all areas of the filter
including the center, middle and outer area of the filter.
A filter cleaned using an alternate cleaning process must have less than 1.5 inches of ash
remaining in the cells if it is to be reused on an engine. Failure to meet this criterion will increase
the risk of filter damage. The 1.5 inch level is considered minimum acceptance criteria.
Follow the measurement procedure detailed in this publication.
When do I reset the ash accumulators?
Ash accumulators can be reset when installing a new filter, replacement filter or a filter cleaned to
0.5” of ash or less. Additionally, a filter that has been removed, inspected and contains less than
1.5 inches of accumulated ash can be reinstalled and the ash accumulator reset.
If the accumulator is reset on a filter that does not meet the above criteria, there will be no
accurate warning lamps for driver notification for the next change/clean interval. Since
Detroit does not approve of DPF alternate cleaning methods, it is the customer’s
responsibility to determine the next mileage point at which to conduct a filter cleaning.
Failure to perform a filter cleaning may result in an over-full filter. Over-full filters are more
prone to localized high heat and cracking. Also, higher-than-normal engine back pressure
will be experienced with a negative impact on performance and fuel economy.
How do I reset the ash accumulators?
The ash accumulators must be reset using DiagnosticLink™ tool.

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ADDITIONAL INFORMATION
Detroit’s filter design, cleaning intervals and cleaning process have been designed as a
comprehensive maintenance package. The reliabilt cleaning process ensures ash levels are less
than 1/8 in. after cleaning. This requirement ensures that filters are able to provide consistent
performance throughout the lifecycle and avoid costly damage to both the filter and engine that can
result from improper maintenance.
Detroit is committed to providing industry leading technology and continuously strives to lower
overall operating costs for our customers. As we continue to learn and develop this technology, we
will work with our customers to educate and enhance our offerings.

CONTACT INFORMATION
For more information regarding the advantages of the Detroit proprietary filter cleaning process,
contact your local Detroit service provider.