Brass sensor next to oil pressure sender
 

What is this thing called? It's got a single connection on the outside and it's very small.

Its the sender for the water temp gauge.

Hey wonder if I should change the one on my cosmo to the 12A one, any difference>?

I think they are all the same. I have one off a 13B 6 port on my 12A.

Thanks anthony :)

They are not all the same. Somewhere along the line Mazda changed the thread pitch. Take the old one with you when you get the new one to make sure its the correct threads.

What about one out of an 80 Rx-7?