How do you install a thermostat on a 1999 Ford Expedition V8?

Piece of cake. Remove the intake bonnet, PS fluid reservoir bracket (that screws into the Thermostat housing), two (long) screws that hold down the housing, lift and separate. No need to remove upper rad. hose from housing neck. Replace thermostat (arrow-head up) and O-ring on housing. Replenish lost anti-freeze.

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The sudden failure of an inexpensive part can leave you and your vehicle stranded by the side of the road. This is especially true of the cooling system thermostat. The thermostat resides in between your engine and your radiator and acts as a temperature controlled engine coolant valve. If the valve fails, so does your cooling system and an overheated engine, and driver, often are the unfortunate end result. The good news is thermostats are inexpensive and relatively easy to replace.

Thermostat

Removal & Installation

1. Disconnect the negative battery cable.

2. Drain and recycle the engine coolant.

3. Remove the power steering reservoir support bracket.

4. Remove the upper radiator hose at the thermostat housing.

5. Remove 2 thermostat housing retaining bolts and remove the housing.

6. Remove the thermostat and O-ring from the lower intake manifold. Discard the O-ring.

To Install:

7. Clean the O-ring sealing surfaces.

8. Install a new O-ring, on the thermostat and position the thermostat in the lower intake manifold.

9. Place the thermostat housing on the lower intake manifold and install 2 retaining bolts. Tighten the bolts to 15-22 ft. lbs. (20-30 Nm).

10. Install the power steering reservoir support bracket.

11. Fill the engine cooling system.

12. Connect the negative battery cable.

13. Start the engine and allow it to reach normal operating temperature while checking for coolant leaks.

14. Road test the vehicle and check for proper engine operation.

15. Check the coolant level and add if necessary.