I have a 1985 Camaro, originally v6. Now has a 350.
Temp gauge recently stopped working – needle wouldn’t movefrom cold. If I ground the green wire going to the sender in the head (driver’sside) the gauge reads hot. Based on this I decided to get a new sensor.

No matter where I look I can’t seem to find a part# for the sensor in my car. It is 3/8” NPT with the round terminal.
Here is a pic:
https://www.dropbox.com/s/cv8j4tu3jt7ljc2/temp%20sensor.jpg

So I broke down and went with this one:
http://www.oreillyauto.com/site/c/detail/BWD0/WT359.oap?keyword=wt359
which is 3/8” NPT, but has a slightly different connector.

The WT359 is installed now, but the gauge still doesn’twork. The gauge reads hot when cranking the engine, so I presume that the gauge, wiring & ground at the sensor/head is good.

Any direction would be appreciated!

 

The temp sensor is pretty universal for our cars, one that fits a 305 will fit a 350. I'd just go to AZ or equivalent and buy one for any Camaro/Firebird with a 305 or 350 that looks like yours. That would work just fine for you. Also, if you can't find one with the round terminal, get one without it and cut your pigtail to match the new sensor, they should operate the same.

 

That is exactly what I did and I am still stuck without a working water temp gauge.

 

Sounds like you used too much Teflon tape on the sensor threads, and didn't tighten it enough; so the shell of it isn't actually making contact with the metal of the casting.

Tighten it a bit more.

 

Thanks for the advice. I pulled the sensor out, removed all of the Teflon tape and tightened it as much as I could. Same issue, the gauge moves to hot when cranking the engine, then returns to cold and stays there as the engine heats up.

 

What's the voltage on the terminal when it's cold (key on engine off), and what's the voltage on the shell?

 

I am really glad you asked that. Tested voltage on the terminal...... 0 volts. Found that the 28 yr old wire was in pretty rough shape. Replaced wire and terminal - back in business!

Thanks for the help!