How to Replace a Thermostat in a 2002 Ford Ranger

The thermostat on a 2002 Ford Ranger regulates the amount of antifreeze that flows through the engine and back into the radiator. When the fluid reaches 190 degrees, the thermostat opens to reduce the restriction of flow. The fluid cools off as it passes through the radiator, keeping the Ranger from overheating by eliminating excessive heat within the aluminum heads of the engine. This reduces the possibility of costly head warping.

Things You'll Need

• Pliers
• Towel
• 9/16-inch socket
• Ratchet

Instructions

1. Trace the top radiator hose from the location where the hose is clamped to the inlet tube on the radiator to the point where the hose clamps to the T-Stat housing on the Ranger. This is the easiest way to locate the thermostat since the thermostat rests inside of the T-Stat housing.

2. Remove the pressurized band clamp from the radiator hose. The clamp is a traditional compression clamp. Squeeze the two tabs on the top of the clamp together with a pair of pliers. This relieves the clamp of pressure. With the tabs squeezed, pull the hose off the T-Stat housing and immediately hold the hose vertical to force the antifreeze back into the radiator. A small amount of antifreeze could get onto the top of the engine. If so, wipe it off with a towel

3. Remove the two 9/16-inch bolts that secure the T-Stat housing to the Ranger's intake manifold. Use a socket and ratchet to remove the bolts.

4. Pull the T-Sat housing off the intake manifold. Inspect the bottom of the housing for the paper T-Stat housing. Remove it and clean the surface area with a towel. Clean any leftover gasket material off the surface of the intake manifold with a towel.

5. Pull the old thermostat out of the intake manifold with your fingers and place the new one into the manifold. The end with the large spring sits inside of the intake manifold while the end with the long pin sticks up into the T-Stat housing.

6. Place the new paper T-Stat housing on top of the intake manifold and then set the T-Stat housing on top of the paper gasket. Bolt the T-Stat housing into place with the 9/16-inch bolts.

7. Squeeze the compression tabs on the radiator hose clamp and slide the hose back onto the T-Stat housing. Release the tabs on the clamp to apply clamping pressure onto the radiator hose.

References

• "Ford Ranger Repair Manual Years 1993 to 2010"; Haynes; 2010