I need to replace the water temp sender for my Smiths Telemetrix gauge but I'm unsure which thread it is.
The Merlin motorsport web site lists 2 sizes 1/8 NPT and 5/8 NPT and I'm unsure which one I have.

The diameter of the threaded part on the sender is approx 10mm. Can you tell from that which one it will be? I think it is 1/8 NPT as it is fitted to the bottom of a Zetec thermostat housing but I want to be sure before ordering.

Cheers
Stu.

[Edited on 24/11/09 by stuart_g]

1/8 NPT

Yep, thread on the bottom of the thermo is 1/8npt, btw, does anyone know the thread of the top one?

Burtons list as M12x1.5.

Thanks All.