I've seen threads on this before, I know it happens in the FC but mine is like 100X worse. In the other threads, it stops after some time. Mine just keeps on going off for ever! It turns off for up to thirty seconds when I'm slowing down, but never for long. I cant take it anymore its sooo off putting!! How do I straight up disconnect it? I think I know which wire it is. But if I just rip it out will it just continue to go off? Please help. Very annoyed.

 

You're 100% sure the sensor is bad?

If so.. Then clip the wire at the nut on top of the radiator and ground it [Do NOT cut off the connector, you'll need that when you get a new sensor!]

 

Well the sensor doesn't look broken...but I don't think it's the car because it has plenty of coolant and the temp is fine. I found a break in the wire that was frayed. I cut it, and wrapped the two together and tapped it up for now. I'll see how it is tomorrow. I have a new radiator on its way and I'll get a new sensor while I'm at it.

 

Have you checked the coolant level in the radiator by taking off the radiator cap? (not when engine is hot) I had the same issue after I had my engine rebuilt, but all I needed to do was top the coolant in the radiator. The manual mentioned that the coolant buzzer comes on if engine oil is low as well, but I've never let it go low enough to know that for sure. Hope this helps.

 

I've had same issue with two different RX7's when coolant level is full. (Oil level within normal range as well). Solution both times was a coolant flush/fill due to an air bubble getting trapped near the sensor for the coolant level (which couldn't be fixed by adding more coolant). I flush coolant every other year anyway, and the issue did not recur afterwards.

This may not be what is happening to you, but this is what worked for me.

 

I had this same problem recently after parking my TII for 5 months while I went to work in Alaska. Got back the other day, hooked up the battery and went to start it and the buzzer was going off. Topped off the coolant, drove it a couple of times and then it started going off again, but the coolant was topped. Drained and flushed the system, then refilled it and its been fine for the last week or so.
Prior to parking it I had blown a heater hose and replaced all the hoses in the coolant system, then didnt have much time to really test it out much after that. So could be air bubbles in the system.

 

Burp it.

 

What he said.

Grab the lower radiator hose and keep squeezing and releasing it. It helps work bubbles out.