Stock temp block

[Warren]

So why would the stock temp sender have a 18 mm hex head? It would be nice to know what the exact specs are as I have several resistors in line on my driver car and I rather find a proper thermistor or however it's spelled to achieve a better reading stock water temp gauge.

Maybe the 18 mm is a industrial part or translates to Witworth

I remember a stock discussion of the only place Witworth fasteners was used was on the heater valve...

 

[mr55s]

Witworth

I'm pretty sure Witworth fasteners were also used in the seats.
Brian