I went to flush my cooling system and change the thermostat on my Mk1 Golf.
All went fine until I put the new coolant in. There is a pretty steady leak from the thermostat housing.
I've tightened the screws as much as I feel safe doing, but it wont stop.
What surprised me when I was removing the old thermostat was that there was no gasket or seal around where thermostat housing attaches - only an O-ring on the thermostat its self.
Would anyone know that I can do or if I've done something wrong?