Cadillac 12600171 Thermostat, Engine Coolant

Before removing the thermostat for cooling issues, check the coolant level, drive belt tension, and temperature gauge. Next, drain the cooling system, remove the air filter housing duct, locate and open the thermostat housing, and remove the seal as well as the radiator hose.

Before assuming the thermostat is to blame for a cooling system problem, it is important to check the coolant level, drive belt tension, and temperature gauge (or light) operation. Before starting the replacement process, it is important to disconnect the cable from the negative terminal of the battery and partially drain the cooling system, saving the coolant if it is in good condition. If the fitting that mates with the hose deteriorates, replace the thermostat housing. The thermostat housing can be removed by removing the bolts and tapping it with a soft-face hammer if it is stuck. The mating surfaces on the engine and the thermostat housing should be cleaned, and a new O-ring should be installed in the groove in the housing. The thermostat housing should then be reattached to the intake manifold or water pump housing, depending on the model, and the bolts should be tightened to the proper torque specifications. Finally, the cooling system should be refilled, the engine should be run, and carefully checked for leaks.

Carefully position the cover, install the bolts without over-tightening them, refill the cooling system, start the engine, and check for leaks and proper thermostat operation.

To install the thermostat, begin by cleaning the sealing surfaces and inspecting the hoses for replacement if needed.

1. Remove the air filter housing and air intake duct. 2. Drain the cooling system and save the coolant if it is in good condition. 3. Remove the coolant reservoir. 4. Remove the thermostat housing cover, which depends on the engine. 5. Replace the housing cover if the large fitting that mates with the hose is deteriorated. 6. Remove the old gasket material or sealant from the housing cover. 7. Install a new rubber seal over the thermostat. 8. Install the new thermostat with the spring end directed into the engine. 9. Reattach and tighten the housing cover to the proper torque specifications. 10. Reattach the hose and tighten the hose clamp securely. 11. Install all components that were removed for access. 12. Refill the cooling system. 13. Start the engine and allow it to reach normal operating temperature to check for leaks and proper thermostat operation.

If the engine runs hot and the lower radiator hose is not hot, it is likely that the thermostat is stuck closed, preventing coolant circulation.

If the engine seems to be taking a long time to warm up, indicating that the thermostat is stuck open, it should be replaced with a new one.