Thermostat

REMOVAL & INSTALLATION

1979–85 Vehicles

1. Position a pan and drain the cooling system. (The system can be drained by disconnecting the lower radiator hose.)

   NOTE: If the coolant is clean and you are planning on reusing it, be sure the drain pan is also clean so it will not contaminate the coolant.

2. On carbureted (Code 12A) engines, remove the air cleaner assembly.
3. Disconnect the upper radiator hose from the engine, then remove the two nuts or bolts attaching the thermostat housing cover.
4. Remove the cover, then lift out the thermostat and gasket.
5. Carefully scrape any old gasket material from the mating surfaces.

   To install:

6. Position a new gasket, and install the thermostat with the jiggle pin facing up.
7. Attach the thermostat cover and tighten the retaining nuts or bolts.
8. Connect the upper radiator hose and tighten the hose clamp.
9. Install the air cleaner assembly (Code 12A engines only).
10. Connect the lower radiator hose and tighten the hose clamp.
11. Fill the radiator to the proper level with a suitable coolant mixture.
12. Start the engine and inspect for coolant leaks.

1986–89 Vehicles

1. Position a pan under the radiator drain plug. Open the plug and drain the cooling system.

   NOTE: If the coolant is clean and you are planning on reusing it, be sure the drain pan is also clean so it will not contaminate the coolant.

2. Loosen the hose clamp and disconnect the upper radiator hose.
3. Disconnect the water thermoswitch terminal at the thermostat cover.
4. Remove the two bolts and separate the cover from the engine.
5. Remove the thermostat and gasket from the housing.

   Fig. 1: Thermostat assembly — 1979–85 RX-7

   Fig. 2: Thermostat assembly — 1986–89 RX-7

6. Carefully scrape any old gasket material from the mating surfaces.

   To install:

7. Position a new gasket onto the housing. Install the thermostat into the housing so that the jiggle pin is facing up.
8. Install the cover and tighten the retaining bolts.
9. Attach the water thermoswitch connector to the terminal on the cover.
10. Using a moderate twisting motion, connect the upper radiator hose by aligning the marks on the hose with those on the cover. Tighten the hose clamp.
11. Check that the drain plug is closed, then fill the radiator to the proper level with a suitable coolant mixture.
12. Start the engine and inspect for coolant leaks.