Turbocharger Cup Plug Field Fix Kit DDC P/N: 23528679


On a small number of Series 60/50 wastegate turbochargers there have been reports of the cup plugs coming
loose. The symptoms are: Loss of power and lack of turbo boost. If you encounter this condition, do not
replace the turbocharger, inspect and replace the wastegate cavity cup plug. The
“Cup Plug Field Fix Kit” DDC P/N: 23528679 (Garrett P/N: 721976-2) is designed as a replacement part kit
for field repair of turbine housing waste gate assemblies which have damaged or missing cup plugs. The kit
is for use on GT42, GT47, and GT50 model turbochargers.


For Detroit Diesel applications, P/N 23528679 “Cup Plug Field Fix Kit” (Garrett P/N: 721976-2) is for use
on, but not limited to, turbochargers with serial numbers of CCL00001, CCM00001, CCP00001, and later.
“Later” refers to turbocharger build date, which is described by the first two characters of the serial number.
The first character is a YEAR CODE and the second character is a MONTH CODE.
Based on “A” representing 1971; “B”, 1972; and so on through
“Z”, 1996, and then starting over with “A” in 1997.

Based on “A” representing January; “B”, February; and so on
through “L”, December, and then starting again with “A” in
Serial number “CCL00001” was built in 1999 (determined from the first C) during the month of March
(determined from the second C). A “Later” serial number would be “CEL00001” which was built in 1999
during the month of May.
The third character “L, M, or P” represents a Facility Code and does not effect the turbocharger build date.

Check that vehicle ignition is off, wheels blocked, and follow all applicable shop safety regulations.
Allow engine, exhaust, turbocharger, and all other related parts to cool completely.
Locate and visually inspect the turbocharger turbine housing waste gate assembly.
If the cup plug (press fit freeze plug) is damaged or missing proceed. If cup plug is in tack, continue with
standard trouble shooting procedures.

Remove the exhaust tube and other related hardware from the turbine housing outlet. (Note: there may
be no need to disassemble or remove the turbocharger, only remove the exhaust line attached to the
turbine outlet.)

If the cup plug is missing from the turbine housing, attempt to locate the missing part.
Note: If the cup plug remains in the exhaust line it
may cause further damage to the turbocharger and/or
the exhaust system and vehicle.

At this time verify that there is no other damage to the turbocharger, for example: does the waste gate and
actuator operate properly? Does the turbine wheel spin freely? Consult appropriate service manual and

Installation of Seal Plug P/N 721539-3 (Item 1 in part list)
Visually inspect the cup plug bore. If staking impressions are large, resulting in excess raised metal
around the outside staked surface, use a die grinder or file to flatten this area before installation. (See
Figure 2) This area needs to be flat for proper settling of Cap Plug (Item 2). Also, if the internal bore is
deformed from the staking or excessively corroded, grind or file where needed.

Insert “Seal Plug” (Item 1) into turbine housing through the waste gate cavity. (See Figure 3 and 4)
Insert “Long Bolt” (Item 3) into “Cap Plug” (Item 2)
With the Long Bolt (3) and Cap Plug (2) together, thread the Long Bolt (3) into the Seal Plug (1).
Use the bolt from the outside and your hand on the inside of the housing to position the Seal Plug so that
it seats squarely inside the turbine housing bore.
Note: If Seal Plug (1) does not seat squarely
it will be damaged when pulled into place by the
installation bolt (Long Bolt 3).
Continue threading Long Bolt (3) into the Seal Plug (1). Torque until the lip on the Seal Plug (1) begins
to seat on inside cast surface of the turbine housing.
Note: The Long Bolt (3) is only used as an installation
bolt for seating the Seal Plug (1). It must be replaced
by the Short Bolt (4) in order for correct operation of
the turbocharger.
Remove the Long Bolt (3). Visually verify that the Seal Plug (1) is seated Properly. (See Figure 5)

Final Assembly and Torque
Replace Long Bolt (3) with Short Bolt (4).
Torque Short Bolt (4) to 300 +/- 25 in-lb (25 +/- 2 ft-lb)
Note: If Short Bolt (4) is not used in final assembly,
the turbocharger will not operate properly.

Re-assemble Exhaust
Replace the exhaust tube and other related hardware to the turbine housing outlet in reverse order of

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