Tools and supplies

• 3/8" Ratchet
• 6" extension
• 10mm socket (for two thermostat housing nuts)
• 8mm socket (Throttle body cover bolt and radiator hose clamp)
• Clamp pliers or needle nose pliers (clamp on 7/8' hose above thermostat housing)
• Torque wrench
• Bungee cord
• Empty one gallon container
• Five foot length of 3/16" id (5/16"od) windshield washer hose

Procedure

1. Remove the radiator cap (only on a cold engine!) and insert the 3/16" hose all the way to the bottom of the radiator. Siphon out about one gallon of coolant.
2. Remove the one bolt on the throttle body cover using ratchet and 8mm socket and then remove cover. (Improves your visibility)
3. Unhook electrical cable to throttle body. (Easier to get ratchet in and out)
4. (This step is not strictly necessary, but it does make the job easier). Loosen hose clamp on upper radiator hose using ratchet, 8mm socket and 6" extension. Pull hose off the thermostat housing and bend it forward toward the front of the car and "bungee" it in that position. This is a good time to replace the upper radiator hose if it's showing signs of aging.
5. Using clamp pliers or needle nose pliers, slide the clamp on the 7/8" hose, that is at about the 11 o'clock position in relation to the thermostat housing, about two inches back on the hose. This makes it easier to get the housing on and off. You DON'T have to remove the hose.
6. Using a ratchet, 10mm socket and 6" extension remove the two 10mm nuts holding the thermostat housing in place and remove the housing. The housing should come away easily as there is no gasket. Note exactly how the thermostat is placed - the body toward the engine and the two small bleed holes at the top.
7. Pull out the old thermostat. Clean all mounting surfaces and put in the new thermostat (jiggle valves at 12 o'clock position).
8. Reattach the thermostat housing and torque two 10mm nuts to 6-8 ft. lbs. Do not overtighten! The studs go into alloy and won't take much to strip.
9. Reattach 7/8" hose clamp; reattach radiator hose; reattach throttle body electrical cable; reattach throttle body cover; refill coolant. Check for leaks.
10. You may need to add coolant after a few warmup/cool down cycles.

    I used the Ford thermostat part #E9DZ*8575B and paid $24.10. A Robertshaw unit (492-192) is available for about $8 at most auto parts stores.

    I removed a full gallon of coolant and had no mess when I removed the thermostat housing. When I replaced the coolant, I got everything back into the radiator except about one pint. I put this in the overflow tank.

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