Ford F-250: How to Replace Thermostat

The thermostat is designed to open up when the engine reaches a certain temperature to let coolant in. If it fails, you risk overheating and perhaps ruining the whole engine.

By Pizzaman711 - December 17, 2014

This article applies to the Ford F-250 and F-350 Super Duty (2005-2014).

The thermostat sits between the engine and the radiator of your Ford F-250 or F-350 Super Duty. It is designed to block the flow of coolant to the radiator until the engine has warmed up. Your thermostat reduces engine wear, deposits, and emissions.

Materials and Tools Needed

  • Socket wrench and socket set
  • Coolant
  • Thermostat
  • Gasket
  • Pliers
  • Drain pan

Step 1 - Drain your coolant

You're going to get under your Super Duty and find the drain valve and allow the coolant to drain out. You don't have to let all of it out. You can also use a clean drain pan here so that you can reuse your coolant after you're done.

Figure 1. Drain the coolant out of the radiator.

Step 2 - Remove the intake piping

You'll need to remove the intake piping from the throttle body to the air box in order to reach the thermostat housing.

Figure 2. Remove the intake piping.

Step 3 - Remove the upper radiator hose on the thermostat housing

Now, you should be able to see the clamp holding the upper radiator hose to the thermostat housing. Take a pair of pliers and slip the clamp back so you can remove the upper radiator hose.

Figure 3. Remove the upper hose on the thermostat housing.

Step 4 - Remove the thermostat housing

Grab your socket wrench and sockets again to remove the two bolts holding the thermostat housing to the intake manifold. They are long bolts, but the threads are short.

Figure 4. Remove the thermostat housing.

Step 5 - Replace the thermostat

Now you can reach your thermostat to replace it. Your new thermostat should come with the o-ring gasket, but if it didn't, be sure to buy and install it before you install the new thermostat.

Figure 5. Install the new thermostat.

Step 6 - Put it all back together

Now you should put everything back in the opposite order in which you removed it. When it comes time to putting coolant back in, be sure to use the right coolant! The 2005 to 2014 F-250 and F-350 Super Duty use Motorcraft Gold, so you'll have to get some from your dealer or a retail store or just reuse the coolant in the drain pan if it's clean.

Figure 6. Refill with coolant.

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