PARTS STOCK ACTION ONLY - NEW AND REMANUFACTURED CYLINDER HEADS IN PARTS STOCK NEED TO BE REWORKED TO INCLUDE ADDITIONAL COO LANT FLOW PASSAGES - PI7281 - MAILED US AND CANADA, CACO, COFA, BRAZIL, CFEL, COSA, TRUCK TEPS Caterpillar

PARTS STOCK ACTION ONLY - NEW AND REMANUFACTURED CYLINDER HEADS IN PARTS STOCK NEED TO BE REWORKED TO INCLUDE ADDITIONAL COO LANT FLOW PASSAGES - PI7281 - MAILED US AND CANADA, CACO, COFA, BRAZIL, CFEL, COSA, TRUCK TEPS

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Caterpillar: Confidential Yellow

PARTS STOCK ACTION ONLY - NEW AND REMANUFACTURED CYLINDER HEADS IN PARTS STOCK NEED TO BE REWORKED TO INCLUDE ADDITIONAL COO LANT FLOW PASSAGES - PI7281 - MAILED US AND CANADA, CACO, COFA, BRAZIL, CFEL, COSA, TRUCK TEPS

NOTE: The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.


March 27, 1992
U-50
A-35
AU-31
B-23
E-28
O-43
TT-7
PARTS STOCK NEW AND REMANUFACTURED CYLINDER HEADS IN PARTS
ACTION ONLY STOCK NEED TO BE REWORKED TO INCLUDE
ADDITIONAL COOLANT FLOW PASSAGES
1100  PI7281

Termination Date

June 30, 1992

Problem

Certain new and remanufactured cylinder heads in parts stock, for use on
various arrangements of 3406, 3406B, and 3406C Engines, need to be reworked
to include an additional coolant flow passages.

Parts Needed

1 - 2B0858 Plug-Pipe
1 - 2M6471 Plug-Cup

Action Required

Remove all of the following cylinder heads and cylinder head groups from
parts stock. Inspect and rework if necessary. See the attached rework
procedure.
0R1158 Cylinder Head  0R2155 Cylinder Head
0R1160 Cylinder Head  0R2156 Cylinder Head
0R1161 Cylinder Head  7W0009 Cylinder Head
0R2104 Cylinder Head  7W2204 Cylinder Head

Service Claim Allowances

Submit one claim for all 0R1158, 0R1160, 0R1161, 0R2104, 0R2155, 0R2156,
7W0009, 7W2204 Cylinder Heads removed from parts stock and reworked. No time
will be allowed for inspection only.
One hour per cylinder head will be allowed for doing the rework as described
in the attached procedure.

Parts Disposition

Return all reworked cylinder heads to parts stock.
Attach. (1-Rework Procedure)
Rework Procedure
Inspect all 0R1158, 0R1160, 0R1161, 0R2104, 0R2155, 0R2156, 7W0009, and
7W2204 Cylinder Heads in parts stock for the existance of a 1/2" pipe plug.
Inspect the top rear surface of the cylinder head on the centerline which
coincides with the nozzle holes. A pipe plug in this location indicates the
head already contains the two drilled coolant passages. If a plug is not
visible, the head must be reworked. These two new passages through the top
and intermediate decks of the head will improve coolant flow through the rear
of the head. Remove the core (cup) plug from the rear face of the cylinder
head. The rear head coolant passage and exhaust port wall will be visible.
Measure the distance from the rear face of the head to the wall of the
exhaust port. This dimension will vary on every cylinder head due to casting
variations. Locate the centerline of the new drilled hole so that the drill
bit does not contact the exhaust port wall. Do this by subtracting a minimum
of 8.1 mm (.32") from the measured dimension. Locate and mark the cylinder
head center line. (See illustration.) This centerline extends through the
nozzle adapter holes. The first step is to use a 19/32" drill bit and drill
a 15 mm (.594") diameter hole 85 mm (3.35") deep. (approximately 25.4 mm
(1.00") from the bottom surface of the head). Do not exceed this depth as
damage to the bottom deck may occur. Use the existing hole as a pilot. Use
a 23/32" drill bit and enlarge the hole to 18 mm (.719") diameter and to 20
mm (.79") deep. Tap the hole to accept an 1/2-14 NPTF threaded pipe plug.
Remove the existing pipe plug from the right rear corner of the cylinder head
top deck. Visible inside is a 5 mm (.20") diameter bleed hole. Use a 19/32"
drill bit and enlarge this hole to a 15 mm (.594") diameter by drilling 85
mm(3.35") deep. Use care not to contact and damage the existing pipe threads.
Clean up threads if necessary.
NOTE: Some of the former version heads have a 3/8" pipe plug in this
location. The 3/8" pipe plug can be retained by drilling a
slightly smaller hole than mentioned above or it can be enlarged
to a 1/2 in. plug size using the above instructions.
Clean the chips from both holes using a magnet. Install the new and
previously removed pipe plugs with thread sealant. Press in a new 2M6471
core (cup) plug with 7M7456 Bearing Mount on outer diameter to prevent
leakage.
****** IMAGE: SEBE4827.00001.001
CAPTION: Illustration 1
****** IMAGE: SEBE4827.00001.002
CAPTION: Illustration 2