Yowdy...

I have this Montero with about 175,000 miles on it. It has the dash coolant temp gauge problem where it's shorted out and doesn't work/fluctuates.

I installed an analog water temp gauge in the larger of the two sensor ports that sit next to each other on the intake manifold.

I unplugged both before installing new sensor, one at a time and together and the dash gauge acted the same. Furthermore, the motor ran fine. I removed the larger 2-wire sensor, which is apparently the ECU sensor (I didn't know this at the time) and placed the new sensor inside of it and ran the Montero for 35 minutes verifying temperature and that it runs fine. It seemed to be totally fine even though I diconnected the ECU sensor. Vehicle got up to 185-190 degrees F in about 5 minutes and ran smoothly. I revved the motor several times through 4,500 RPMs during the 35 minutes. Tested A/C and Heat, etc. All seems normal.

2 questions...

Does anyone know what this sensor does for the vehicle and how it 'should' behave if it's disconnected as I have done? It has Mitsubishi part numbers of
MD177572 and MD182467 (one supercedes).

The aftermarket analog mechanical sensors will not fit in the port of the gauge sensor (the smaller sensor with a single wire connection, part number MD091056). I'm unsure if there is another port to use for the aftermarket sensor...I don't see one. Is there one?

Thanks!