PRODUCT SUPPORT PROGRAM FOR REPLACING CYLINDER HEADS, WITH INTAKE VALVE RECESSION, ON CERTAIN 794 AC OFF-HIGHWAY TRUCK ENGINES Caterpillar

PRODUCT SUPPORT PROGRAM FOR REPLACING CYLINDER HEADS, WITH INTAKE VALVE RECESSION, ON CERTAIN 794 AC OFF-HIGHWAY TRUCK ENGINES

Usage:

TEBE5162-01

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18Oct2016

(Revised 29Sep2017)

U-554

A-400

D-472

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After Failure Only	PRODUCT SUPPORT PROGRAM FOR REPLACING CYLINDER HEADS, WITH INTAKE VALVE RECESSION, ON CERTAIN 794 AC OFF-HIGHWAY TRUCK ENGINES
1100 1105 1103		PS53325

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NOTE:	Caterpillar’s obligations under this Service Letter are subject to, and shall not apply in contravention of, the laws, rules, regulations, directives, ordinances, orders, or statutes of the United States, or of any other applicable jurisdiction, without recourse or liability with respect to Caterpillar.
NOTE:	This Program can only be administered after a failure occurs. The decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS53325" as the Part Number and "7755" as the Group Number. Use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.

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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.

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NOTE:	This Revised Service Letter replaces the 18Oct16 Service Letter. Changes have been made to the Title, Problem, Affected Product, and Parts Needed.

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TERMINATION DATE

31Oct2018

PROBLEM

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The existing cylinder heads can experience intake valve recession on certain 794 AC Off-Highway Truck Engines. If the existing cylinder heads experience intake valve recession, it can result in a valvetrain failure.

Intake valve recession has been sporadic in nature on the majority of engines in the field. Valve recession is more prevalent on inboard intake valves. Some sites and applications have experienced more widespread intake valve recession. Electric drive trucks have shown a higher rate of intake valve recession.

AFFECTED PRODUCT

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Model	Identification Number
794 AC	MN500052-00056 MT500100-00115

PARTS NEEDED

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Qty	Part Number	Description
1	8C3132	SEAL-O RING
4	8T2223	BOLT-SOCKET HD
1	8T9524	SEAL-O-RING
1	20R7042	HEAD GP-CYL BSC
1	2287089	SEAL-O-RING-ORFS
1	2287100	SEAL-O-RING-STOR
1	2287108	SEAL-O-RING-STOR
1	2300940	SEAL
1	2435741	SEAL-FUEL SYSTEM
1	2435742	SEAL-FUEL SYSTEM
1	2464924	GASKET
1	2589925	GASKET-COMB
1	2589926	GASKET
1	2697852	SEAL-O-RING
1	3170808	SEAL-O-RING
1	3708028	SEAL-INTEGRAL
In order to allow equitable parts availability to all participating dealers, please limit your initial parts order to not exceed 20% of dealership population. This is an initial order recommendation only, and the ultimate responsibility for ordering the total number of parts needed to satisfy the program lies with the dealer.

ACTION REQUIRED

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The maximum amount of valve recession is limited to 2mm (0.08in) of wear. The nominal head deck to valve stem tip measurement is 60.538mm (2.383in). Any cylinder head with head deck to valve stem tip measurement that exceeds 62.538mm (2.462in) should be replaced.

1. Monitor and adjust the valve lash as recommended per the Operation and Maintenance Manual.

2. Track lash measurements at each adjustment interval and monitor for valves that get tighter over time.

3. Measure the recession on the suspect cylinders.

4. Replace any head that meets or exceeds the 2mm (0.08in) recommended replacement for intake valve recession.

Note: Projection of wear at a given hour interval out to full life will not be allowed for head replacement. Only heads exceeding 2mm recession will be allowed.

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Image1

SERVICE CLAIM ALLOWANCES

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Product smu/age whichever comes first	Caterpillar		Dealer Suggested		Customer Suggested
Product smu/age whichever comes first	Parts %	Labor Hrs%	Parts %	Labor Hrs%	Parts %	Labor Hrs%
0-20000 hrs, 0-48 mo	100.0%	100.0%	0.0%	0.0%	0.0%	0.0%

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NOTE: This is a 6.0-hour job If there has been a previous repair, part age/hours will apply. Retain a copy of the previous repair invoice in the dealer's records for audit purposes, and specify repair date and machine hours in the "Additional Comments" section of the warranty claim.
Documentation of lash measurements and adjustment history on engine must be provided with claim. Multiple cylinder heads can be claimed so long as documentation is provided to justify the number of heads replaced. Labor allowance is per cylinder head. Service Letter can be claimed multiple times throughout the life of the engine so long as hours on the cylinder head is established. Projection of wear at a given hour interval out to full life will not be allowed for head replacement. Only heads exceeding 2mm recession will be allowed