Disconnect the negative battery cable.
Do not remove pressure cap with the system hot and under pressure because serious burns from coolant can occur.
Drain the cooling system into a suitable container
Disconnect the radiator lower hose from thermostat housing.
Remove nuts from the heater tube flange studs.
Loosen the starter bolt at heater tube bracket.
Pull the heater tube out of thermostat housing and position out of the way.
Remove the thermostat housing (1), O-ring (2) and thermostat (4).
Remove the thermostat housing bolts (3).
To install: Thoroughly clean the gasket sealing surfaces.
Install the thermostat with the bleed valve located at the 12 o'clock position, between tabs on seal.
Install the thermostat and seal (2) into thermostat housing (1).
If removed, install the two studs.
Lubricate a new heater return tube O-ring with coolant.
Position the heater return tube flange over the two studs. Install the 3 retaining nuts and torque to 53 inch lbs. (6 Nm).
Tighten the starter bolt to 40 ft. Lbs. (54 Nm).
Connect the lower radiator hose to the thermostat housing. Install the hose clamps.
Refill cooling system
Connect the negative battery cable. Start and warm the engine. Check for leaks.