1991 Pontiac Sunbird Repair Question
The thermostat is located inside a housing on the back of the cylinder head. It is not necessary to remove the radiator hose from the thermostat housing when removing the thermostat.
1. Disconnect the negative battery cable.
2. Properly drain the cooling system into an approved container.
3. Remove the air cleaner.
4. On some models it may be necessary to disconnect the A.I.R. pipe at the upper check valve and the bracket at the water outlet.
5. Disconnect the electrical lead.
6. Remove the two retaining bolts from the thermostat housing and lift up the housing with the house attached. Lift out the thermostat. Clean the mating surfaces.
7. Apply a 1 / 8 in. (3mm) bead of silicone sealer to the housing mating surface.
8. Place the thermostat, with the power element down, in housing, then install the water outlet while the sealer is still wet. Tighten the housing retaining bolts to 6 ft. lbs. (8 Nm).
9. Connect the electrical lead.
10. If applicable, attach the A.I.R. pipe at the check valve and bracket at the water outlet.
11. Install the air cleaner.
12. Fill the cooling system to the proper level, using the correct type of fluid.
13. Connect the negative battery cable, then start the engine and check for coolant leaks.
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