SWITCH AS-LIMIT 9X4394 - 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 after a failure occurs. The decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS0501" as Part Number, "7755" as Group Number, and "96" as Description Code.
Termination Date
April 30, 1993Problem
A failed sleeve or sleeve to head joint 3176 Truck Engines may cause fuel dilution of the cooling system, coolant entry into the injector cavity, or coolant entry into the cylinder.
Affected Product
Mode & Identification Number
3176 (2YG4902-9368*)
*If not previously reworked and stamped with "3S" next to Serial No. PlateParts Needed
4 - 7C2597 Gasket (water lines)5 - 8C3684 Antifreeze (gal) (if contaminated with fuel)6 - 3H2388 seal-O ring (spacer to head)6 - 4P7135 sleeve6 - 5P8066 O-ring (upper injector)1 - 1S7057 Gasket (turbo oil supply)1 - 7W2398 Gasket (turbo drain)6 - 9X7722 O-ring (lower injector)1 - 9Y7044 Gasket-Cylinder Head (only if head needs removal)Action Required
1. When it is necessary to replace a sleeve due to failure of the sleeve or the sleeve to head joint:a) Check for 3S stamped on the block next to the serial number plate. If block is stamped with 3S, change only the failed sleeve using 4P7135 sleeves. The 4C6730 Roller Expander and 4C6714 Swage must be used to install the new sleeves. See Special Instruction SEHS9246. Failure on engines marked 3S should be filed as normal warranty.b) If block is not stamped 3S replace all six sleeves using 4P7135 sleeves. The 4C6730 Roller Expander and 4C6714 Swage must be used to install the new sleeves. See Special Instruction SEHS9246.2. Ream all sleeves and check injector sleeve seating surface in head. Install the injector and check for good seat using blue dykem.3. Stamp 3S in the block next to the serial number plate after work is complete.Engine Disassembly
Cylinder Head Removal - It is possible to replace the sleeves without removing the cylinder head. See Special Instruction SEHS9246. However, in some applications it may be more efficient to remove the head. This decision is left to the dealer. Reason to remove the head must be explained in the claim story.
Off Engine Test
Test electronic unit injectors for leaks and VOP on test bench if milage is less than 150,000 mi. Replace as necessary.
Engine Assembly
1) Pressurize the cooling system to 15 psi. Look for leakage in and around sleeve cavity to check installation process. Replace any leaking sleeves.2) Test for fuel leaks past the upper injector O-rings by blocking the fuel return line and pressurizing to 100 psi. (observe for 3 minutes)3) Install the remainder of the parts to complete assembly of the engine.4) If failure resulted in fuel in the coolant, flush and fill cooling system. Flush the system for a minimum of 30 minutes using 4C4609/4C4613 Cleaner (may use 6V4511 as a substitute).