Thermostat — checking operation (Opel Vectra A)

1. A rough check of the thermostat can be done as follows. Hang it on a piece of string in a container filled with water. Heat the water to boiling - at the moment of boiling the thermostat should open. If this is not the case, replace it.

2. If you have a thermometer, measure the exact temperature at which the thermostat starts to open and compare it with the data given in SpecificationsThe thermostat opening temperature is also marked on the thermostat itself (see illustration).



3. A thermostat that does not close after the water has cooled should also be replaced.

(Text was copied from the portal OPELBOOK)