A few months ago I bought a 99 Monte Carlo LS 3.1 and notice the temperature gauge only goes up around 1/3 of the way. So jumped the connector and the gauge also jumped. Well I also noticed the last owner put green antifreeze in it so figure once the weather cools off a little change that out and replace the sender. BUT despite my repair manual showing a sender and a sensor whenever I try to look up the part it only shows me the sensor. Am I looking up the wrong name for it or something? Cause the manual has a picture of both of them for the 3.1. Or does it happen they are the same thing cause when I look up the part all I get is the sensor and not a sender.

 

There is a level sensor that is below the radiator cap on the radiator, and the temperature sensor sets next to the thermostat housing. I use green anti-freeze with no issues.

 

So the temperature sensor also connects to the gauge on the dash or something? It's just a pain cause the repair manual has 2 different pictures for the sender and sensor.

 

The sender drives the temperature gauge, the sensor gives you a low coolant level light.