PULLEY 1W4438 - Caterpillar

All 5.75"
and 6.25"
Bore Six Cylinder EnginesReference: "Inserts And Tools Are Available To Install Larger Diameter Inserts In Cylinder Liner Counterbores" Service Magazine, August 30, 1976; "New Inserts To Repair Cylinder Liner Seats on D353 Engine Blocks" Service Magazine, July 11, 1977When a cylinder block for the above engines is cracked in a counterbore for the cylinder liner, the cylinder block can be repaired if the counterbore is machined larger and an insert is installed. Two inserts are available for each size engine. For the 5.75" Bore six cylinder engines, the 5P1625 Insert and the larger 5P6595 Insert are used. For the 6.25" Bore six cylinder engines, the 5P936 Insert and the larger 5P8607 Insert are used.
It is now Caterpillar's recommendation that only the larger inserts be used to repair the cylinder blocks. Field reports have shown that a few cylinder blocks have cracked again with the smaller insert installed. Use of the larger insert is a more permanent repair for the cylinder block than the smaller insert. Also, the smaller insert can not be used on cylinder blocks that have cracks that are completely around the circumference of the counterbore. The larger insert can be used on any cylinder block with cracks in the counterbore.
After the larger insert is installed on 5.75" Bore engines, it is possible to have a coolant leak around the studs and into the lubricating oil on a few engines. See the top of Page 21 on Special Instructions "Installation of 5P6595 Insert for Cylinder Liner Seat", Form No. SMHS7049. To prevent the coolant leak, put seals over the studs on both sides of the cylinder head gasket. At location (C), (See the Special Instruction) use 5P5598 Seals. At location (D), use 8L2746 Seals. A silicone adhesive can also be used with the seals.
Always install new seals on the studs if the cylinder head is removed. Failure to install new seals can cause coolant leakage into the lubricating oil.