Beretta V6-173 2.8L (1989)
Thermostat: Testing and Inspection
If the thermostat sticks open, the engine will warm up very slowly. If the thermostat sticks closed, the engine will overheat.
Inspect and test the thermostat using the following procedure:
1. Drain the coolant until it is below the level of the thermostat, then remove the water outlet assembly.
2. Remove the thermostat. Unless obviously faulty, test the thermostat as follows before replacing it with a new one:
a. Place the thermostat and a thermometer in a container with a 50/50 solution of water and ethylene glycol antifreeze. Place the container over a
heater. While heating, do not rest either the thermostat or the thermometer on the bottom of the container; this will cause them to be at a higher
temperature than the solution.
b. Agitate the solution to ensure uniform temperature of the solution, the thermostat and the thermometer.
Note The thermostat valve should start to open at the rated temperature. It should be fully open after the temperature has increased 15° C (27°
F).
A used thermostat can be about 6° C (10° F) above or below these settings without adverse affect and should not be replaced. If the thermostat does not
operate at the temperatures specified, replace it; it cannot be adjusted.
