How to change the thermostat in a Ford Powerstroke Diesel

Changing a the thermostat in a Ford Powerstroke 7.3 liter diesel isn't that hard if you have the basic tools and knowledge. By following these step you can save some money by doing it yourself.

Difficulty: Moderate

Instructions

Things You'll Need:

• New thermostat
• New thermostat gasket
• pliers
• 10 mm socket
• gasket sealant

1. First make sure the engine is cool and drain radiator. See my article about how to drain the engine coolant here:
   http://www.ehow.com/how_4746973_engine-coolant-ford-powerstroke-diesel.html

2. It may be easier to do if you loosen the serpentine belt and get it out of the way of the thermostat housing, but doesn't need to be fully removed.

3. 
    
   thermostat housing

   Locate the thermostat housing, which is on the right side of the water pump on the front of the engine.

4. Remove the radiator hose by pinching the clamp with the pliers. Slide the clamp up the hose away from the housing and remove the hose.

5. 
    
   Theromostat still in housing

   Now loosen the 3 bolts holding the housing to the water pump. It should be a 10mm socket. The one on the back side can be a little tricky to get to. Remove the housing. Now you will see the thermostat.

6. 
    
   Housing with thermostat removed

   Now remove the thermostat. You may need to pull out the rubber gasket that seal the thermostat in. Make sure you clean the area around the thermostat before pulling it out to avoid getting dirt in the water pump.

7. 
    
   Picture of the actual thermostat

   Clean the surface of the housing and install new thermostat. Put the new rubber gasket in place. I like to put a small amount of silicone gasket sealer around the housing to make sure it doesn't leak.

8. Replace the thermostat housing and tighten the 3 bolts.

9. Replace the radiator hose and clamp.

10. Replace the serpentine belt, if removed, and refill the radiator with coolant.

11. Start engine and test for leaks.