Replaced what I assume was the original thermostat with a recommended Febi 24028 item, rated at 89c opening.
What I took out was in poor shape, though not causing any obvious problem.
As summer turned to winter, it became obvious that the engine was not getting up to normal operating temperature with this thermostat.
I replaced this with an OE 8200772985 thermostat, and warm up time & normal operating time has returned to what it was.
I tested the Febi thermostat once removed, and it opened at 73 degrees C.
I accept that this may have been a faulty item, but I will test any thermostat before fitment in future.
What I took out was in poor shape, though not causing any obvious problem.
As summer turned to winter, it became obvious that the engine was not getting up to normal operating temperature with this thermostat.
I replaced this with an OE 8200772985 thermostat, and warm up time & normal operating time has returned to what it was.
I tested the Febi thermostat once removed, and it opened at 73 degrees C.
I accept that this may have been a faulty item, but I will test any thermostat before fitment in future.