Thread size on temperatur plugg waterpump Fiat 850?

[Tiller]

Anyone that knows what the thread size on the slott i assume is for a temp sensor on the water pump from a 70' Fiat 850?

 

[F123C]

That's a drain plug for the water pump, used when draining down the coolant system. (Iirc the thread size is 8x possibly 1.5mm?, maybe remove the plug to check the thread?)

The temperature sensor is on the cylinder head. Iirc on the 850, it also clamps a banjo fitting, attached to some by-pass hoses, to the cylinder head.

AL.