18112-ZY6-010ZA Honda COVER, EX. MANIFOLD *NH8* (Honda Code 8445082). (DARK GRAY)

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.
This Program can be administered either before or after a failure. In either case the decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS4049" as the Part Number and "7755" as the Group Number. If administered before failure, use "56" as the Warranty Claim Description Code and use "T" as the SIMS Description Code. If administered after failure, use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.
Termination Date
July 31, 1998Problem
The high pressure turbochargers on certain 793 and 793B Trucks can have a short service life due to compressor seal or thrust bearing reliability. Also, the air inlet pipes can leak boost. A new turbocharger has an improved compressor seal and thrust bearing. The new turbo's cast iron compressor housing, new pipe, adapter and high temperature o-ring will prevent boost leaks.
Affected Product
Model & Identification Number
793 (3SJ1-99999)
793B (1HL1-99999)
Swing Engines
3516 (2PK1-1401 6CL1-227 7CL1-386 54Z1-1168 )
When submitting a claim on a swing engine, use 99Z00021 as the serial number and list the engine serial number in the claim story.
Parts Needed
2 - 7E2340 Gasket 4 - 7E4107 Seal 4 - 8L2746 Seal-O-Ring 6 - 8L2786 Seal-O-Ring32 - 2N2766 Locknut 2 - 7N7559 Gasket 4 - 7N7628 Gasket 2 - 4P4460 Gasket 2 - 4P4867 Seal-Ring20 - 5P7128 Bolt-Washer 4 - 5P8940 Seal-O-Ring 2 - 5P9890 Seal-O-Ring 2 - 0R7186 Turbo Group 2 - 6V3835 Seal-O-Ring 8 - 6V3917 Seal-O-Ring 2 - 6V4589 Seal-O-Ring 4 - 6V5103 Seal-O-Ring 2 - 2W0752 Gasket 4 - 336033 Seal-O-Ring 4 - 1278269 Seal-Exhaust 2 - 1335998 Adapter 2 - 1417140 Pipe 4 - 1433629 Seal-O-RingOptional Parts
2 - 1417164 Plate 2 - 1417165 Adapter 2 - 1417166 Block 2 - 1417167 Elbow16 - 1473737 BoltAction Required
Parts Stock
Remove all 0R6966, 4P4693, 1064557, 1213850, and 1283321 Turbo Groups and all 0R6758, 0R7097, 4P6031, 1020281, and 1330817 Turbo Cartridges from Parts Stock.
Affected Product
See the attached rework procedure.
Service Claim Allowances
Parts Stock
Submit one claim for all 0R6966, 4P4693, 1064557, 1213850, and 1283321 Turbo Groups and all 0R6758, 0R7097, 4P6031, 1020281, and 1330817 Turbo Cartridges removed from Parts Stock.
Affected Product
Allow an additional 4 hours labor for modifying the adapters shown in Illustrations 3 through 6.
Allow one additional labor hour per turbocharger if the turbochargers need the 1255375 Bolts replaced with 1473737 Head Bolts.
Parts Disposition
Return all turbo groups and cartidges removed from Parts Stock to:
Caterpillar, Inc.
Attn: Reference PS4049
501 Cardinal Drive
Corinth, MS 38834
Handle all other parts in accordance with your Warranty Bulletin on warranty parts handling.
Attach.(1-Rework Procedure)Rework Procedure
1. Drain the engine coolant.2. Remove both high pressure turbos. Remove both intake pipes and adapters on top of the aftercooler housings within the 9Y8914 Air Lines Group.3. Examine the type of bolt holding the cast iron compressor housing to the bearing housing on each 0R7186 Turbo. If the bolts are 1255375 Bolts, shown in Illustration 1, remove them and install eight 1473737 Bolts as shown in Illustration 2. The 1473737 Bolts have a ground head to increase clearance. If the bolts are already the 1473737, as shown in Illustration 2, no changes are needed.4. Install four 6V3917 O-Rings and two new style 1433629 O-Rings on each new 1417140 Pipe.5. Lubricate the o-rings with any oil based lubricant. Before installing any iron on the engine, use a dead blow hammer to install the pipe with o-rings into a cast iron adapter and the other end of the pipe into the cast iron compressor housing of the turbocharger. Do this for both sets of pipes, adapters, and high pressure turbos.6. Install the two turbo/pipe/adapter assemblies on the engine.7. Even with the above 1473737 Ground Head Bolts installed, additional clearance is needed to install the turbo water and oil line adapters. The additional clearance comes from modifying the existing turbo water and oil line adapters or by installing the new parts as below:- turbo water inlet adapters--rework the existing 1070744 adapters as per the information in Illustration 3, or install two new 1417166 Adapters.- turbo oil drain adapters--rework the existing 9y5814 adapters as per the information in Illustration 4, or install two new 1417167 Adapters.- turbo oil inlet adapters--rework the existing 6I0804 Adapters as per the information in Illustration 5, or install two new 1417165 Adapters.- turbo water outlet adapters--rework the existing 7E7518 Adapters as per the information in Illustration 6 or install two new 1417164 Adapters.8. Refill coolant. Start engine and check for leaks.
Illustration 1
Illustration 2
Illustration 3
Illustration 4
Illustration 5
Illustration 6