Thermostat — replacement Ford F150
Warning: Wait until the engine is completely cool before beginning this procedure.
Note: Cover the drivebelts with kitchen plastic-wrap. If coolant gets on the belts it can ruin them.
1. Disconnect the cable from the negative battery terminal (see Battery – disconnection and reconnection).
2. Drain the cooling system (see Tune-up and routine maintenance). If the coolant is relatively new and still in good condition, save it and reuse it.
3. Remove the air duct between the air filter housing and the throttle body if necessary (see Fuel and exhaust systems).
4. Follow the lower radiator hose to the thermostat housing. It’s a good idea to cover the drivebelt and components under the thermostat with plastic.
Remove the thermostat cover mounting bolts — 2.7L engine shown
5. Remove the fasteners and detach the thermostat cover (see illustration). If the
cover is stuck, tap it with a soft-face hammer to jar it loose. Be prepared for some coolant to spill as the gasket seal is broken.
Note: The radiator hose can remain attached to the thermostat housing cover.
Note the locations of the jiggle valve; it should be at the top (12 o’clock position)
6. Note how the thermostat is installed with emphasis on the position of the small jiggle valve (see illustration), which should be at the 12 o’clock position, then remove the thermostat 0-ring and thermostat.
7. Clean the housing and cover of all dirt and scale.
8. Position the thermostat into the housing with the jiggle valve at the top. Place a new 0-ring gasket against the thermostat, then install the housing cover and tighten the bolts to the torque listed in this Chapter’s Specifications.
9. Refill the cooling system (see Tune-up and routine maintenance) and reconnect the battery (see Battery – disconnection and reconnection).
10. Start the engine and allow it to reach normal operating temperature, then check for leaks and proper thermostat operation