1. Gather the necessary tools and materials.
- Replacement thermostat (37°C or 100°F)
- 5/16-inch wrench
- 1/2-inch wrench
- Socket wrench set
- Coolant (50/50 mix of water and ethylene glycol)
- Drain pan
- Funnel
2. Locate the thermostat housing.
- The thermostat housing is located on the front of the engine, just below the upper radiator hose.
3. Drain the coolant.
- Place the drain pan under the radiator and open the petcock valve located at the bottom of the radiator.
- Allow all of the coolant to drain into the pan.
4. Remove the thermostat housing.
- Use the 5/16-inch wrench to loosen the bolts holding the thermostat housing in place.
- Carefully remove the thermostat housing, taking care not to spill any coolant.
5. Remove the old thermostat.
- Use the 1/2-inch wrench to loosen the bolts holding the thermostat in place.
- Carefully remove the old thermostat from the housing.
6. Install the new thermostat.
- Insert the new thermostat into the housing, ensuring that the spring side of the thermostat is facing the engine.
- Secure the thermostat with the bolts you removed earlier.
- Tighten the bolts until snug.
7. Reinstall the thermostat housing.
- Carefully place the thermostat housing back onto the engine.
- Secure the housing with the bolts you removed earlier.
- Tighten the bolts until snug.
8. Refill the coolant.
- Use the funnel to add coolant to the radiator until it is full.
- Make sure to use a 50/50 mix of water and ethylene glycol.
9. Start the engine and check for leaks.
- Start the engine and let it run for a few minutes.
- Check for any leaks around the thermostat housing and radiator.
10. Turn off the engine and top off the coolant.
- Turn off the engine and allow it to cool down completely.
- Check the coolant level and top it off if necessary.
That's it! You have now successfully replaced the thermostat on your 1977 442 Oldsmobile.
