Hardening, shrinkage, or damage of both gaskets and O-rings after disassembly can reduce sealing performance.
Remove old gaskets and clean the sealing surfaces thoroughly so that no gasket material or other material remains.
Install the new gaskets and replace the used O-rings when re-assembling.

Force
Liquid Gasket, Non-permanent Locking AgentInner Tube Inspection
Visually inspect the inner tube [A].
If there is any damage, replace the inner tube. Since
damage to the inner tube damages the oil seal, replace
the oil seal whenever the inner tube is replaced.
NOTICE
If the inner tube is badly bent or creased, replace
it. Excessive bending, followed by ...
Thermostat Inspection
Remove the thermostat (see Thermostat Removal).
Inspect the thermostat valve [A] at room temperature.
If the valve is open, replace the thermostat with a new
one.
To check valve opening temperature, suspend the thermostat
[A] in a container of water and raise the temperature
of ...
Water Temperature Sensor Output Voltage Inspection
NOTE
Be sure the battery is fully charged.
Turn the ignition switch to OFF.
Remove the throttle body assy (see Throttle Body Assy
Removal in the Fuel System (DFI) chapter).
Disconnect the water temperature sensor connector and
connect the measuring adapter [A] between these connectors
...