RAIL AS 4649707 - Caterpillar

Failure to replace your water temperature regulator on a regularly scheduled basis could cause severe engine damage.Caterpillar engines incorporate a shunt design cooling system and require operating the engine with a 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. Ensure that the water temperature regulator vent hole is open.Do not use liquid gasket material on the gasket or cylinder head surface.
Refer to Disassembly and Assembly, "Water Temperature Regulator - Remove and Install". Consult your Caterpillar dealer for more information.Note: If only the water temperature regulators are replaced, drain the coolant from the cooling system to a level that is below the water temperature regulator housing.