Step 1. Remove the thermostat housing

Not an easy task, all of three screws were stuck. Applied some anti rust solvent and went ahead with the job the next day.

The housing were heated up by using a butane torch and in addition I used an impact screwdriver to get the screws loose.

Finally I had the parts separated

Cleaning of the parts using the ultrasonic washer

Step 2, verify the function of the thermostat:

According to the service manual the vale opening temperature is 82 deg C and wide open (8mm)  at 95 deg C.

82 deg C and closed

85 deg C and half opened

90 deg C and almost fully opened

Good to go, the thermostat is functioning as specified.

Thermostat response time:

See how it’s closing only seconds after it is out of the boiling water.

Step 3, polishing the thermostat housing:

Nice and shiny 🙂