561M Pipelayer Cooling System Water Temperature Regulator - Clean/Replace Caterpillar

Cooling System Water Temperature Regulator - Clean/Replace

Replace the thermostat on a regular basis in order to reduce the chance of unscheduled downtime and of problems with the cooling system.

A new thermostat should be installed after the cooling system has been cleaned. Install the thermostat while the cooling system is completely drained or while the cooling system coolant is drained to a level that is below the thermostat housing.


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.

  1. Loosen the hose clamp and remove the hose from the elbow. Disconnect the hose assembly from the thermostat housing assembly.

  2. Remove the bolts from the elbow. Remove the elbow and the thermostat housing assembly.

  3. 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 AVSpare 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.

  4. Install a new seal in the thermostat housing. Install a new thermostat and a new gasket. Install the thermostat housing on the engine cylinder head.

  5. Install the elbow and the hose. Tighten the hose clamp.