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How-to » Engine » Mechanical, Lubrication & Cooling » How to Replace a Thermostat
 Note: This is a general guide and may not apply to your vehicle.

How to Replace a Thermostat

for the 2005 Ford F-150 XLT 8 Cyl 5.4L change
PARTS
  • Thermostat Gasket
  • Thermostat
TOOLS
  • Screwdriver
  • Cooling System Pressure Tester
  • 3 more tools
STEPS
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Moderate
Safety Tip: Always wear safety glasses when working on your vehicle. Wear other personal protective equipment (PPE) when necessary, for example latex gloves or closed toe shoes.
1
Be sure the engine and radiator is cold before beginning the next steps. Open the hood and locate the vehicle's radiator.
2
Remove the vehicle's radiator cap and use a radiator pressure tester to check for leaks. 7058
3
Drain out some of the engine coolant in the radiator so the coolant level is below the thermostat housing to prevent leaking when replacing the thermostat.
4
If necessary, remove the upper radiator hose.
5
Remove the thermostat housing bolts. 6590
6
Remove the thermostat housing. 6216
7
Remove the thermostat.
8
Clean the mounting surfaces. Install the new thermostat as it was removed (note proper direction) and always use a new thermostat gasket. Be sure the gasket is correctly positioned over the thermostat.
9
Reinstall thermostat housing and tighten mounting bolts evenly. Take care to not over tighten the bolts. If applicable, reconnect the upper radiator hose.
10
Refill the cooling system with coolant (usually a 50 / 50 mixture of water and anti-freeze). 7046
11
Start the vehicle with the radiator cap off and allow the engine to run for several minutes. This allows the air bubbles to escape the cooling system.
12
Reinstall the radiator cap.
13
Run the engine until up to normal operating temperature. Remember to keep an eye on the temperature gauge to prevent overheating.
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