Thermostat: Service and Repair

1. Disconnect cooling fan switch connector from switch on thermostat housing.
2. Remove radiator pressure cap.

WARNING: Ensure engine is cool prior to servicing.

3. Drain cooling system to a level below thermostat housing.
4. Disconnect upper radiator hose from thermostat housing, then remove housing retaining bolts.
5. Remove thermostat and gasket.
6. Clean mating surfaces of housing and cylinder head, then install thermostat in cylinder head, valve end first with jiggle valve at the top.
7. Coat new gasket with water resistant sealer B5A-19554-A or equivalent, and position it on cylinder head. The painted side of the gasket must face the thermostat. Ensure bolt holes are correctly aligned.
8. Install thermostat housing, ensuring that the gasket does not shift. Install two retaining bolts and torque to 14-22 ft lb.
9. Connect upper radiator hose to thermostat housing, then fill system with recommended coolant mixture and install pressure cap.
10. Connect cooling fan switch connector, then start engine and allow to run until warm.
11. Ensure system is pressurized, then check for leaks.