Sender - Water Temp (1/4" NPT)

Marine Water Temperature Sender 1/4" NPT  (not very common)

 Use 5/8" socket to remove/install

Testing your existing sender: with engine at full temp. and gauge reads "60" or cold, take a ground wire jumper and ground one end and touch the other end of the jumper to the existing sender wire terminal (can leave the wire on) if the gauge swings to full hot and then back when the jumper is removed the sender is bad & needs to be replaced.

Use thread sealant on NPT threads