Speedflow 912-M16-02-BLK M16 to NPT 1/8" thread adapter review
If you're looking to adapt a modern 1/8" NPT thread water temperature sender to the stock sender thread, you'll need an adapter. Speedflow have one - part number 912-M16-02-BLK for the black version:
Out of the packet:
It comes with a crush washer:
Fitted to the thermostat housing:
The particular (very cheap) aftermarket water temperature sender doesn't sit perfectly flush before it bottoms out:
The cheap eBay senders are made of very thin brass, and will shear off very easily if you over-torque them - and it doesn't take a great deal of effort to do so, so be careful. We had a slight drip from using the bare adapter and temperature sender, which was fixed with the application of a small amount of teflon tape.
You can find this particular adapter on eBay - (seller link)
or general eBay search.
Just be careful with the general eBay search and make sure that it's the correct size.