Remove the radiator cap in two steps. First turn the cap counterclockwise to the first stop. Then push and turn it further in the same direction and remove the cap.

NOTE
Wet the cap sealing surfaces with water or coolant to prevent pressure leaks.

NOTICE
During pressure testing, do not exceed the pressure for which the system is designed. The maximum pressure is 142 kPa (1.45 kgf/cm², 21 psi).
If the pressure holds steady, the system is all right.
If the pressure drops and no external source is found, check for internal leaks. Droplets in the engine oil indicate internal leakage. Check the cylinder head gasket and the water pump.
Remove the pressure tester, replenish the coolant, and install the radiator cap.
Coolant Deterioration Inspection
Cooling System FlushingDiode Circuit Inspection
Remove the relay box (see Relay Box Removal).
Check conductivity of the following pairs of terminals (see
Relay Box Internal Circuit in this section).
Diode Circuit Inspection
The resistance should be low in one direction and more
than 10 times as much in the other direction. If any dio ...
Water Pump Housing Disassembly
NOTICE
Do not damage the hole wall of the water pump
housing.
Insert a bar [A] into the pump housing [B], and hammer
evenly around the circumference of the mechanical seal
bottom [C].
Take the oil seal [A] out of the housing [B] with a hook [C].
...
Idle Speed Control Valve Actuator Input Voltage Inspection
NOTE
Be sure the battery is fully charged.
Turn the ignition switch to OFF.
Disconnect the idle speed control valve actuator connector
and connect a suitable measuring leads [A] between
these connectors as shown in the figure.
Main Harness [B]
Idle Speed Control Valve Actua ...