SPOOL 1541907 - Caterpillar

Caterpillar: Confidential Yellow
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 only be administered before failure during normally scheduled maintenance to check and/or adjust valve lash. The decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS4763" 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.
Termination Date
May 31, 1993Problem
The service life of the cylinder head gasket can be extended on certain 3306 Truck Engines by removing the cylinder head bolts one at a time, coating them with 6V4876 Molykote, and then tightening them to the standard torque specification.
Affected Product
Model & Identification Number
3306 (5KD1-2271; 63Z5071-19146)
See the restrictions listed under Service Claim Allowances.
Parts Needed
Not Applicable
Action Required
Verify that the engine qualifies for this program. See the restrictions listed under Service Claim Allowances.
1. With the engine at normal operating temperature, perform the compression leak or "bottle test". Refer to "Know Your Cooling System", Form Number SEBU0518, Page 22.2. If the engine passes the compression leak test then remove the air inlet piping, valve cover, and "Jake Brake" if so equipped. Remove or loosen the fuel injection lines to gain access to all of the cylinder head bolts. Do not remove the individual line clamps.
Do not remove more than one cylinder head bolt at a time.
3. Refer to the tightening sequence shown in the Service Manual. Clean any loose debris from around the cylinder head bolts. Remove the first cylinder head bolt as shown in the tightening sequence.4. Inspect the bolt for corrosion on the shank of the bolt. Clean the threads of the bolt with a wire brush and then wash the bolt in solvent.5. Apply a light coat of 6V4876 Molykote to the threads of the bolt, the underside of the bolt head, and to the washer.6. Install the bolt and tighten it to a torque of 250 17 N m (185 13 lb ft). (This is the standard torque specification for these cylinder head bolts.) Do not over tighten any of the bolts.7. Remove the next bolt in the sequence.8. Repeat Step 4 through Step 7 for the remainder of the cylinder head bolts.9. Adjust the valves as described in the Service Manual.10. Install or tighten the fuel injection lines. Install all other items removed.11. Use the hand priming pump to bleed the fuel system. Start the engine and check for leaks.12. Stamp the serial number plate in the "Modification" space with the letters "HB". ("HB" for head bolt)Service Claim Allowances
This program cannot be applied if:A) Either one of the following Service Letters has been implemented...December 1, 1990 - PS6039; Product