i recently purchased a 2004 mitsubishi montero limited.
yesterday i noticed that the temperature gauge gone completely crazy.
i would start the car without even driving it and the temp gauge will show MAX heat, the car is obviously not hot- i just started it.
turned it off and then restarted it and its back to normal.
today i drove it 4 miles temp showed normal, parked it for 30 mins.
started it back up and temp was on max heat again, restarted the car- normal again.
drove it back heat spiked to max after driving it for 1/2 a mile and went back to normal again after a minute.

the car wasn't overheated, it cant be over heated when i just started it. didnt feel or looked over heated, the AC was blowing cold air.
took the car to AUTO ZONE to see if any codes showed up- none! no error codes at all.
coolant level looks good.
any ideas? i was thinking it might be the temp sensor but it doesnt show a code for it.

 

Unfortunately this is a very common issue with the instrument gauge cluster on Monteros. Search the forum. There are several threads about it including repair guide if you are good with electronics and soldering. It is unnerving and very annoying to have this happen. Fixable.

 

As what HunterD just said....do a search in this forum and you will have your problem solved.

 

Cheap, interim option: OBD /bluetooth device on ebay and download an App like Torque (Android) . One can load a couple of displays to run in real time on their phone

 

PRRnTX...same thing I did to check if my temp guage is really acting up. I also used the Torque app to diagnose my o2 sensor issues and my egr issues. So investing in those blue tooth obd devices is really a good idea.

 

Which OBD device do you use? Need one for my 2001 Montero which has the same issue.

 

=StuckWithMyTruck
used a couple OBD2/Bluetooth , but never one of the "mini" devices. Recommend a later model which has additional protocols for domestic manufactures. The Torque site has some really good info... including If one orders a ' cheap device'.
These are always on when plugged in with very little milliamp draw on the battery. Still, I tried the small one with the blue on/off switch, but bumped it with my knee and found that when it is turned off while the ignition is active, it interfered/cut off the speedometer display (but unsure if it temp. opened or shorted another circuits on the Mitsubishi). Instead of looking at a schematic, I pulled it out and used another.