Thermostat: Service and Repair

Removal

1. Drain the cooling system so that the coolant level is below the thermostat as outlined.
2. Disconnect the healer return hose at the thermostat housing located on the left front lower side of engine.

CAUTION: DO NOT PRY TO REMOVE.

3. Remove the coolant outlet housing retaining bolts. Pull the elbow away from the cylinder head or manifold sufficiently to provide access to the thermostat. Remove the thermostat and gasket.

Installation

1. Clean the coolant outlet housing and cylinder head and water pump gasket surfaces. Coat a new gasket with Perfect Seal Sealing Compound B5A-1 9554-A or equivalent. Position the gasket on the cylinder head opening. THE GASKET MUST BE POSITIONED ON THE CYLINDER HEAD OR THE INTAKE MANIFOLD BEFORE THE THERMOSTAT IS INSTALLED.

TO PREVENT INCORRECT INSTALLATION OF THE THERMOSTAT, THE WATER OUTLET CASTING CONTAINS A LOCKING RECESS INTO WHICH THE THERMOSTAT IS TURNED AND LOCKED. INSTALL THE THERMOSTAT WITH THE BRIDGE SECTION (FIGS. 2 AND 3) IN THE OUTLET CASTING. TURN THE THERMOSTAT CLOCKWISE TO LOCK IT IN POSITION ON THE FLATS CAST INTO THE OUTLET ELBOW.

FIG. 2 Engine Thermostat and Housing - Disassembled View:

FIG. 3 Thermostat installation:

It is imperative that the correct thermostat installation alignment be made to provide coolant flow to heater (Fig 2.). Insert and rotate thermostat assembly to the left or right until it stops in the water outlet housing - then visually check for full width of heater outlet tube opening to be visible within the thermostat port in assembly (Fig. 3). This port alignment at assembly is required to provide maximum coolant flow to the heater.

2. Position the coolant outlet elbow against the cylinder head, intake manifold or, water pump. Install and tighten the retaining bolts to specifications.
3. Connect heater hose to thermostat housing.
4. Fill the cooling system with the recommended Cooling System Fluid E2FZ-1954-A or equivalent, and water mixture as outlined. Check for leaks and proper coolant level after the engine has reached operating temperatures.