SCREW 4B9806 - Caterpillar

Jacket Water Temperature Regulator
Illustration 1 g02997422
Replace the water temperature regulators (1) before the water temperature regulators fail. Replacement is a recommended preventive maintenance practice. Replacing the water temperature regulators reduces the chances for unscheduled downtime.A water temperature regulator that fails in the closed position can cause excessive overheating. Excessive overheating could result in cracking of the cylinder head or a seizure of the pistons.A water temperature regulator that fails in the open position will cause the engine operating temperature to be too low during partial load operation. Low engine operating temperatures during partial loads could cause an excessive carbon buildup inside the cylinders. This excessive carbon buildup could result in an accelerated wear of the piston rings and wear of the cylinder liner. Also, a low temperature can allow moisture to condense in the oil. This condensation can form damaging acids.
Failure to replace the water temperature regulator on a regularly scheduled basis could cause severe engine damage.Never operate an engine without the water temperature regulator installed.If the water temperature regulator is installed incorrectly, the engine may overheat, causing cylinder head damage. Ensure that the new water temperature regulator is installed in the original position.
For the procedure to replace the water temperature regulators, see the Service Manual, "Disassembly and Assembly" module. Consult your Cat dealer for assistance.Note: If only the water temperature regulators are replaced, drain the coolant from the cooling system. Only drain to a level that is below the water temperature regulator housing.Separate Circuit Aftercooler (SCAC) Temperature Regulator
Illustration 2 g02915086
Replace the water temperature regulators (2) before the water temperature regulators fail. Replacement is a recommended preventive maintenance practice. Replacing the water temperature regulators reduces the chances for unscheduled downtime.The SCAC temperature regulator maintains the incoming water at the required minimum temperature.Fluctuations in the SCAC inlet water temperature will adversely affect engine performance and emissions.For the procedure to replace the water temperature regulators, see the Service Manual, "Disassembly and Assembly" module. Consult your Cat dealer for assistance.