Product Support Program For Inspecting And Tightening Cylinder Head Bolts On Certain C-12 Truck Engines That Have Had The Head Gasket Replaced At A Previous Repair Caterpillar

NOTE: This Program can be administered either before or after failure.In either case the decision whether to apply the Program is made by the dealer.When reporting the repair, use "PS40105" as the Part number and "7755" as the Group Number.If adminstered before failure, use "56" as the Warranty Claim Description Code and use "T" as the SIMS Description Code.If adminstered after failure, use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.

NOTE: This program is to be applied to engines that have had a head gasket replaced during a previous repair.

Termination Date

Problem

The cylinder head bolts need to be inspected and tightened on certain C-12 Truck Engines.

Affected Product
Model & Identification Number

C-12 Truck (1YN1-Up, 9NS1-Up, 2KS361-7938)

Parts Needed

129-3184 Bolt - Reduced Shank(if bolt has any corrosion or pitting on shank, under bolt head or in bolt threads as defined in Step 4 in Procedure 1 CANNOT BE CLAIMED under this letter.

1 - 101-3125 Gasket (use as needed when chassis interference requires removal of Air Inlet Elbow)

1 - 9X-7557 Seal-O-Ring (use as needed when FLD112 chassis interference requires #6 injector removal)

1 - 119-8784 Seal-O-Ring (use as needed when FLD112 chassis interference requires #6 injector removal)

1 - 9X-7317 Seal-O-Ring (use as needed when FLD112 chassis interference requires #6 injector removal)

Action Required

See the attached procedure.

Service Claim Allowances

NOTE: Procedure 1 maybe claimed under this Service Letter ONLY WHEN ALL 26 BOLTS ARE RETIGHTENED.

NOTE: Procedure 2 can not be claimed against this Service Letter.

NOTE: If it is determined the head gasket has failed in steps 3 and 4 of the rework procedure the labor time to remove, inspect and tighten bolts is to be claimed as troubleshooting time. File ONE CLAIM under the applicable coverage for the Engine.

NOTE: For Recreational Vehicle (RV) & Fire Truck applications ONLY: RV and Fire Truck Engines may require additional labor time (reasonable/actual) for difficult engine access. Claim the total time for rework using 1100-500-BC and include in the claim story why the additional time is required.

Parts Disposition

U.S. and Canadian Dealers:

All 129-3184 Bolts must be returned to:

All other dealers:

Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.

Attach.

(1-Rework Procedure)

Rework Procedure

There are TWO REPAIRS PROCEDURES listed in this Service Letter.

Procedure 1: Defines the procedure for tightening cylinder head bolts WITHOUT REPLACING THE HEAD GASKET.

Procedure 2: Defines the procedure for tightening cylinder head bolts when a head gasket has failed.

NOTE: WHEN REPLACING A HEAD GASKET USE THE NEW TIGHTENING PROCEDURE LISTED IN PROCEDURE 2, IT IS DIFFERENT THAN THE SERVICE MANUAL. PROCEDURE 2 IS ALSO DIFFERENT THAN PROCEDURE 1.

NOTE: Reference SEBF8301 for Guidelines on Inspection and Reuse of Critical Fasteners.

PROCEDURE 1

THIS PROCEDURE DEFINES TIGHTENING CYLINDER HEAD BOLTS WITHOUT REPLACING THE HEAD GASKET. (PROCEDURE 1 IS THE ONLY PROCEDURE THAT CAN BE CLAIMED UNDER THIS SERVICE LETTER)

NOTE: Do not perform tightening procedure 1 on A hot engine.allow THE ENGINE to cool FOR at least four Hours.

NOTE: DO NOT use this procedure when INSTALLING A NEW HEAD GASKET because a short our failure will result.

1. Remove valve covers, valve cover base, Jake Brakes (if equipped), rocker arm assemblies and push rods.

2. Before removing any head bolts. BE SURE THE COOLING SYSTEM IS NOT PRESSURIZED.

3. Remove head bolts (ONE AT A TIME) 15, 17, 19, 21, 23 and 25 and inspect bolt. Inspection of these bolts is being completed out of the normal tightening sequence. If the bolt does not have any of the signs as defined in Step 4, blow out the hole and continue the tightening procedure.

4. Inspect each bolt for corrosion or pitting on shank, under bolt head or in bolt threads. (See Illustration 2)

Illustration 1:

Head bolts to be inspected prior to tightening

NOTE: When a bolt is removed for inspection it is possible coolant may leak into the bolt hole.

Illustration 2:

Inspect bolts for corrosion or pitting.

5. If bolts are free of any corrosion or pitting, reinstall bolt by lubricating bolt threads, washer and under the head of the bolt with 6V4876 Lubricant. Tighten bolt according to the following chart.

6. Turn bolt 90 degrees.

Illustration 3:

(Top) "Type 1" Standard (Full Shank) cylinder head assembly mounting bolt. (Bottom) "Type 2" (Reduced Shank) cylinder head assembly mounting bolts.

NOTE: If any corrosion or pitting is found on the shank, under bolt head or in the bolt threads STOP THE TIGHTENING PROCEDURE and replace the head gasket.

File ONE claim under the head gasket part number.

7. Continue the tightening procedure for bolt # 1 through 14,16, 18, 20, 22, 24, 26. Use tool 161-3440 on bolts 16, 18, 20, 22, 24, 26, because these bolts are under the water manifold.

8. Continue the tightening procedure for bolt # 1 through 14,16, 18, 20, 22, 24, 26. Use tool 161-3440 on bolts 16, 18, 20, 22, 24, 26, because these bolts are under the water manifold.

9. For bolts # 27-33, without loosening, tighten bolt to a torque of 28 N·m (21 lb-ft).

10. Install push rods (use a light to assure the lower end of the push rods are in the sockets of the valve lifters), rocker arm assemblies and Jake Brake (if equipped) according to service manual guidelines.

11. Adjust settings as follows:

* Valve lash

* Inlet = 0.38 mm (0.015 in) Exhaust = 0.64 mm (0.025 in)

* nit injector adjustment

a) Turn adjusting screw clockwise 180 degrees past initial contact with unit injector.

b) While holding adjusting screw in position, tighten lock nut to 55 N·m (41 lb-ft).

* Jake Brake adjustment

C-12 (1YN)= 1.14 mm (.045 in)

C-12 (9NS)= 1.02 mm (.040 in)

C-12 (2KS)= 1.02 mm (.040 in)

12. Replace valve cover base and valve covers.

13. Stamp Engine Information Plate with rework code HB1, in Modification No. area.

PROCEDURE 2

THIS PROCEDURE DEFINES TIGHTENING THE CYLINDER HEAD BOLTS WHEN THE HEAD GASKET HAS FAILED. PROCEDURE 2 CANNOT BE CLAIMED AGAINST THE SERVICE LETTER.