OIL COOLER CORE ASSEMBLY 6N9831 - Caterpillar

Introduction
The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below.Problem
There have been a number of isolated instances of issues with 357-8714 Connection Assembly , 367-1817 Connection Assembly , 367-1818 Connection Assembly and 367-1819 Water Temperature Regulator As on certain C6.6 and C4.4 engines.The water temperature regulator has two jiggle pins that vent the engine cooling system when the engine is being filled with coolant. Either or both jiggle pins may seize in the closed position. This creates an air lock in the engine during initial coolant fill and hence engine damage through overheating.If the water temperature regulator is affected with this issue, the application will not accept the correct volume of engine coolant on first coolant fill.Note: The application may have a full header tank.There will not be any warnings in the application of this issue, but the coolant temperature is likely to remain low. The coolant temperature could be below 70° C (158° F) after 30 minutes of engine operation. The engine is likely to be overheating due to insufficient coolant in the engine or airlocks in the coolant system.Solution
The manufacturing procedure that produces the jiggle pins has been improved.
Illustration 1 g03015663
Typical exampleTo resolve this issue with the water temperature regulator, follow steps 1 to 5.
Remove the water temperature regulator from the engine. Refer to Disassembly and Assembly, "Water Temperature Regulator - Remove and Install" for the correct procedure.
Orientate the water temperature regulator with the jiggle pins facing upwards. Refer to illustration 1.
Invert the water temperature regulator and then return the water temperature regulator back to the original position that is shown in illustration 1. Make sure that the jiggle pins (1) open and close under the effect of gravity.
If either of the jiggle pins (1) do not move, replace the water temperature regulator. Check the jiggle pins in the new water temperature regulator. Refer to steps 2 and 3. If the jiggle pins in the new water temperature regulator move correctly, install the new water temperature regulator. Refer to Disassembly and Assembly, "Water Temperature Regulator - Remove and Install" for the correct procedure. Prior to installing the upper radiator hose and filling the cooling system, follow steps 4.a to 4.b.
If both jiggle pins were seized, the water pump should be inspected for damage. The water pump seal could have been damaged if subjected to dry running. Refer to Systems Operation, Testing and Adjusting, "Water Pump - Inspect" for the correct procedure.
Pour some coolant into the outlet of the water temperature regulator. Observe if the coolant drains into the engine within about 10 to 15 seconds.
Install the upper radiator hose and fill the cooling system. Refer to Operation and Maintenance Manual, "Cooling System Coolant - Change" for the correct procedure to fill the engine cooling system.