GMC 12553405 Housing,Engine Coolant Thermostat

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Begin by draining about three quarts of coolant from the radiator until the level is below the thermostat housing. Disconnect the upper radiator hose from the thermostat housing cover. Remove the nuts/bolts holding the cover and lift it off. It may be necessary to move the belt tensioner bracket aside and tap the cover with a soft-face hammer to break the gasket seal. Note the orientation of the old thermostat and then lift it out. Use a scraper or putty knife to remove any old gasket material and sealant from the mating surfaces, being careful not to let any fall into the coolant passages. Clean the mating surfaces with lacquer thinner or acetone. Apply a thin layer of ATV sealant to the gasket mating surfaces of the housing and cover. Install the new thermostat in the engine with the correct end facing up. Position a new gasket on the housing, ensuring the holes line up with the bolt holes. Carefully position the cover on the housing and install the bolts, tightening them to the specified torque without overtightening to avoid distortion. Reattach the radiator hose to the cover and tighten the clamp. It is recommended to check and replace hoses and clamps at this time. Refill the system with coolant. Run the engine and carefully check for any coolant leaks.

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.

Begin by draining about three quarts of coolant from the radiator until the level is below the thermostat housing. Disconnect the upper radiator hose from the thermostat housing cover. Remove the nuts/bolts holding the cover and lift it off. It may be necessary to move the belt tensioner bracket aside and tap the cover with a soft-face hammer to break the gasket seal. Note the orientation of the old thermostat and then lift it out. Use a scraper or putty knife to remove any old gasket material and sealant from the mating surfaces, being careful not to let any fall into the coolant passages. Clean the mating surfaces with lacquer thinner or acetone. Apply a thin layer of ATV sealant to the gasket mating surfaces of the housing and cover. Install the new thermostat in the engine with the correct end facing up. Position a new gasket on the housing, ensuring the holes line up with the bolt holes. Carefully position the cover on the housing and install the bolts, tightening them to the specified torque without overtightening to avoid distortion. Reattach the radiator hose to the cover and tighten the clamp. It is recommended to check and replace hoses and clamps at this time. Refill the system with coolant. Run the engine and carefully check for any coolant leaks.

It is important to check the coolant level, drivebelt tension, and temperature gauge (or light) operation.