Tools You'll Need:
* New Thermostat: Make sure to buy the correct thermostat for your specific engine.
* New Thermostat Gasket: Essential to prevent leaks.
* Socket Wrench Set: Various sizes, likely including a socket to fit the drain plug and bolts holding the thermostat housing.
* Wrench Set: May be needed for some bolts or hose clamps.
* Pliers: For hose clamps (depending on the type).
* Drain Pan: To catch coolant.
* Funnel: To refill coolant.
* Jack and Jack Stands (Highly Recommended): For easier access and safety.
* Gloves: To protect your hands.
* Coolant: The correct type for your Malibu. Check your owner's manual.
* Rag or Shop Towels: To clean up spills.
Procedure (General Steps - Consult your repair manual for specifics):
1. Safety First: Let the engine cool completely before starting this process. Working on a hot engine is dangerous.
2. Vehicle Preparation: Jack up the front of the vehicle and securely place it on jack stands. This provides much better access.
3. Drain Coolant: Locate the coolant drain plug (usually on the radiator's lower hose connection). Place your drain pan underneath and carefully loosen and remove the drain plug to drain the coolant.
4. Locate Thermostat Housing: The thermostat housing is typically located on the engine block, near the top of the engine, and connected to the upper radiator hose.
5. Remove Thermostat Housing: This often involves removing several bolts holding the housing in place. Be careful as coolant may still remain in the housing.
6. Remove Old Thermostat: Once the housing is removed, the old thermostat should be visible. Carefully remove it, noting the gasket's orientation for reinstallation.
7. Clean the Housing: Thoroughly clean the thermostat housing and gasket mating surfaces of any debris or old gasket material.
8. Install New Thermostat and Gasket: Install the new gasket onto the housing, making sure it's seated correctly. Then carefully place the new thermostat into the housing, ensuring it's oriented correctly (usually a small notch or indentation helps alignment).
9. Reinstall Thermostat Housing: Reinstall the thermostat housing and tighten the bolts to the manufacturer's specified torque (check your repair manual).
10. Refill Coolant: Carefully refill the coolant system using a funnel, adding coolant until it reaches the proper level (check your owner's manual).
11. Bleed the System (Crucial): Air pockets in the cooling system can cause overheating. Consult your repair manual for the proper bleeding procedure for your Malibu. This often involves opening the radiator cap and running the engine briefly to purge air.
12. Check for Leaks: Inspect all connections for leaks after refilling.
13. Test Drive: After letting the engine cool, take the car for a short test drive to ensure the thermostat is working correctly and there are no leaks. Monitor the temperature gauge.
Important Considerations:
* Engine Type: The location and specifics of this procedure can vary slightly depending on the engine in your 1999 Chevy Malibu (2.4L, 3.1L, or 3.8L). A repair manual specific to your vehicle is highly recommended.
* Coolant Type: Use the correct type of coolant as recommended by your owner's manual. Mixing different types of coolant can be detrimental.
* Torque Specifications: Always tighten bolts to the manufacturer's specified torque to avoid damaging the engine or housing.
This is a simplified overview. Always refer to a repair manual specific to your 1999 Chevy Malibu's engine for detailed instructions, diagrams, and torque specifications. If you are not comfortable performing this repair yourself, it's best to take your vehicle to a qualified mechanic.
