How to Replace a Thermostat in a 1988 Mustang

The 1988 Ford Mustang was equipped with either a 2.3-liter four-cylinder engine or a 5.0-liter eight-cylinder engine. Both engines were equipped with a single spring-operated thermostat as part of their cooling systems. A defective thermostat is most commonly associated with engine overheating, since a defective thermostat prevents the engine's coolant from circulating throughout the engine and into the radiator. Replacing the thermostat on either engine takes only a few minutes, and the process is essentially the same.

Instructions

1

Position a container under the radiator's drain cock. The drain cock is located at the bottom of the interior side of the radiator.

2

Open the drain cock with an open-end wrench. Turn it counterclockwise to drain the radiator.

3

Remove the outlet elbow's retaining bolts with a socket wrench to access the thermostat. The upper radiator hose attaches to the outlet elbow on the engine.

4

Pull the thermostat out of the outlet elbow. Turn the thermostat counterclockwise until it detaches from the elbow if replacing the thermostat on the eight-cylinder engine.

5

Remove the old gasket material and engine sealant from the mating surfaces of the outlet elbow and the engine with a gasket scraper.

6

Apply engine sealant to a new thermostat gasket.

7

Position the gasket on the engine.

8

Insert the replacement thermostat in the outlet elbow. Rotate the thermostat clockwise until the thermostat locks into place if working on the eight-cylinder engine.

9

Place the outlet elbow against the engine.

10

Install and tighten the outlet elbow's retaining bolts with a socket wrench.

11

Close the drain cock at the base of the radiator by turning the drain cock clockwise with an open-end wrench.

12

Turn the radiator cap to the left until it detaches from the radiator.

13

Pour the radiator fluid from the container into the radiator.

14

Position the radiator cap on the radiator. Turn the cap to the right until it's secure.