FRAME A 8D4634 - Caterpillar

Failure to replace the engine's thermostat on a regularly scheduled basis could cause severe engine damage.
Note: If you are only installing a new thermostat, drain the cooling system coolant to a level that is below the thermostat housing.
Illustration 1 g01588753
Loosen the hose clamp (1) and remove the hose from the thermostat housing (2).
Remove the bolts (3) from the thermostat housing (2). Remove thermostat housing assembly.
Remove the gasket, the thermostat, and the seal from the thermostat housing.
A used thermostat can be installed if the thermostat conforms to test specifications, and the thermostat is not damaged. Do not install a used thermostat that has 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. Install the thermostat housing (2) on the engine cylinder head. Replace bolts (3) to the thermostat housing and tighten bolts.
Install the hose. Tighten the hose clamp.