A ways back I installed a Borg Warner coolant sender for my IPC coolant gauge. Since my last thermostat install a few months back the gauge needle never gets to the 'N' on the NORMAL scale of the gauge. It gets close when on a 100* day with the A/C on MAX but it usually sits midway between the lowest setting and just shy of 'N' on the gauge.

Now, I've already performed the test where you unplug the sensor and then ground the signal wire. The needle went from one extreme to the next, indicating the gauge is working correctly, as are the wires to it. Do I have a defective sender or should I just get a different brand?

 

It's possible the that thermostat doesn't work. It's been a few years but I paid a couple extra dollars for one of those 'fail safe' thermostats and it failed after a month or two. They default to the open position.

 

That's where my stock gauge always stays, just before the N and occasionally gets to the O idling in traffic on really hot days with the A/C running. This past weekend I installed an aftermarket water temp gauge in the dash and installed the new sender in the factory location and was surprised to see how hot the motor is really running. I run a 170* Tstat and was thinking being so low on the factory gauge that I was at 180* at the most. The new analog gauge shows the actual temp is 190 to 195. From what I've read, a Tstat starts opening at it's advertised temp but isn't fully open until 20* higher, which means mine isn't fully open until 190* which corresponds to the new gauge.

 

^ the factory thermostat is 195° and you are screwing with the computer by running the colder thermostat. It probably doesn't affect you as much living in Florida.

 

You've already diagnosed the problem. If a high-flow thermostat fails open, the engine will never warm up, and rarely get to the "N". I ignored all the advice about the thermostat, but it was right.

 

It's not the thermostat (practically brand new w/ fail safe). I've checked the outlet temp with a thermometer and a temp gun and when the gauge is at its normal spot I've observed anywhere from 190-210. It's in the right range as per the gauge.

 

My (fictional) money is still on the thermostat. A 195° thermostat opens around that temp.

 

Well, like I said, my running temp with the 170 stat is 190 to 195. I have to believe with a 195 stat my temps would be over 210 and I don't want that.