Usage:
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.
NOTE: 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 "PS8079" 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.
NOTE: This Revised Service Letter replaces the December 20, 1993 Service Letter. Changes have been made to the Affected Product.
Termination Date
December 31, 1994Problem
Some naturally-aspirated G3304 and G3306 Engines with three-ring pistons and intake valve stem seals may experience accelerated valve face and seat wear. The wear maybe accelerated to a point where the valve looses lash prior to the valve lash setting check and adjust interval.
Affected Product
Model & Identification Number
G3304 (37Y1852-2145, 37Y2146-2330, 37Y2333-2335, 37Y2352, 37Y2354)
G3306 (07Y3663, 07Y3666-3668, 07Y3671-3673, 07Y3675, 07Y3679, 07Y3681, 07Y3684, 07Y3688-3689, 07Y3692, 07Y3695, 07Y3702-3703, 07Y3705, 07Y3707-3711, 07Y3713-3738, 07Y3740, 07Y3745, 07Y3747-3748, 07Y3750-3752, 07Y3755, 07Y3757-3776, 07Y3791, 07Y3793, 07Y3795-3803, 07Y3805, 07Y3807, 07Y3812, 07Y3815, 07Y3819, 07Y3822, 07Y3824, 07Y3826, 07Y3829, 07Y3831-3837, 07Y3840-3849, 07Y3852, 07Y3854, 07Y3856, 07Y3858, 07Y3861-3863, 07Y3865-3868, 07Y3870-3873, 07Y3875, 07Y3877, 07Y3879-3880, 07Y3882-3884, 07Y3886-3895, 07Y3897-3910, 07Y3912-3914, 07Y3917-3919, 07Y3923-3924, 07Y3926, 07Y3931-3933, 07Y3938-3941, 07Y3945-3946, 07Y3952-3964, 07Y3990-3991, 07Y4001, 07Y4004, 07Y4009, 07Y4012-4016, 07Y4022-4027, 07Y4031-4036, 07Y4041-4048, 07Y4051-4054, 07Y4056-4062, 07Y4064-4067, 07Y4070, 07Y4072, 07Y4077-4081, 07Y4083-4086, 07Y4089-4099, 07Y4106, 07Y4108-4116, 07Y4118, 07Y4125-4126, 07Y4128, 07Y4132, 07Y4137-4138, 07Y4140-4142, 07Y4163-4164, 07Y4173, 07Y4181, 07Y4184, 07Y4187, 07Y4190-4192, 07Y4194-4202, 07Y4206-4209, 07Y4211, 07Y4213-4214, 07Y4218, 07Y4220-4225, 07Y4228-4229, 07Y4231-4235, 07Y4237-4240, 07Y4242-4244, 07Y4247, 07Y4250-4255, 07Y4257, 07Y4261-4262, 07Y4265, 07Y4269-4274, 07Y4276-4278, 07Y3966-3971, 07Y3973, 07Y3975-3985)
Parts Needed
Action Required
Remove the valve cover and pressurize the cylinder to prevent the valves from falling into the cylinder. Depress the spring of the intake valve and remove the locks, rotator and spring in order to access the 7W9143 Valve Guide Seal. remove the seal and discard. Install the spring, rotator, and locks. replace the valve cover. If needed, install new valve cover gasket (G3304 Engines use an 8S1606 Gasket and G3306 Engines use an 8S1605 Gasket. Install valve cover.
Service Claim Allowances
G3304 Engines
NOTE: This is a 1.5-hour.
G3306 Engines
NOTE: This is a 2-hour.
Parts Disposition
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.