STEM ASSEM. 7S2371 - Caterpillar

Personal injury can result from hot coolant, steam and alkali.At operating temperature, engine coolant is hot and under pressure. The radiator and all lines to heaters or the engine contain hot coolant or steam. Any contact can cause severe burns.Remove cooling system pressure cap slowly to relieve pressure only when engine is stopped and cooling system pressure cap is cool enough to touch with your bare hand.Do not attempt to tighten hose connections when the coolant is hot, the hose can come off causing burns.Cooling System Coolant Additive contains alkali. Avoid contact with skin and eyes.
Note: The water temperature regulators (thermostats) should be replaced after the cooling system has been cleaned. Replace the regulators while the cooling system is completely drained or while the cooling system coolant is drained to a level that is below the water temperature regulator housing.
Failure to replace the engine's thermostat on a regularly scheduled basis could cause severe engine damage.
Replace the regulators on a scheduled basis in order to reduce the chance of unscheduled downtime and of problems with the cooling system.
Park the machine on a level surface. Engage the parking brake and stop the engine.
Illustration 1 g01428741
Remove filler cap (1) slowly in order to relieve the pressure.
Illustration 2 g03731311Note: Make sure that the coolant level is below the regulator housing.
Disconnect the hose assemblies from regulator housing (2).
Remove the regulator housing assembly.
Remove the gasket, the regulator, and the seal from the regulator housing.
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 regulator housing. Install a new regulator and a new gasket. Repeat Steps 5 and 6 for the three remaining regulators.
Install the regulator housing assembly on the engine. Connect the hose assemblies to the regulator housing.
Tighten the hose clamps.
If necessary, add coolant in order to restore the coolant to the proper level. Refer to Operation and Maintenance Manual, "Cooling System Coolant Level - Check" for more information.
Start the engine and run the engine at low idle. Check for leaks and make any necessary repairs.