HOUSING AS 3605989 - Caterpillar

Failure to replace the engine's thermostat on a regularly scheduled basis could cause severe engine damage.
Note: If you are only replacing a thermostat, drain the cooling system coolant to a level that is below the thermostat housing.
Illustration 1 g00647667
(1) Thermostat housing assembly
Disconnect the hose assembly from thermostat housing assembly (1).
Remove thermostat housing assembly (1).
Remove the gasket, the thermostat, and the seal from thermostat housing assembly (1).
Former thermostats may be used, if they meet test specifications and are not damaged or have excessive buildup or deposits.
Since Caterpillar engines incorporate a shunt design cooling system, it is mandatory to always operate the engine with a thermostat.Depending on load, failure to operate with a thermostat could result in either an overheating or an overcooling condition.
If the thermostat is installed incorrectly, it will cause the engine to overheat.
Install a new seal in the thermostat housing. Install a new thermostat and a new gasket. Repeat Steps 3 and 4 for the three remaining thermostats.
Install thermostat housing assembly (1) on the engine cylinder head. Connect the hose assembly to thermostat housing assembly (1).
Tighten the hose clamp.