I recently bought a n/a 2001 Se with a little over 138k miles and I have been having overheating issues. Since buying the car I have replaced the radiator,thermostat,cooling fan sensor,cps, and radiator cap. There is no oil in the coolant or coolant in the oil, no boiling water or pockets of air coming out of the cooling system, and the real-time temp reads I am getting are from 199-213' using a Bluetooth obdII and torque app.
The internal gauge hangs in the 2o clock position and at times I have seen it right next to the H but the temps I am getting via obd do not indicate overheating. The fans turn on around 204' and all the hoses are intact. I have some possible ideas as to what the problem may be:

1-Radiator cap and thermostat are not oem from mazda(Aftermarket)
2-Cooling system needs a flush
3-faulty temperature gauge or connection.
4-Bad waterpump
5-Bad timing(Not sure on this, no knocking)

Any feedback would be valuable and appreciated, Thank you.

 

Sounds like you're getting conflicting temp readings from your various gauges. I would change the temp sensor so you know what you can trust before throwing more time/money a a problem that might not exist.

-Ryan

 

I have not changed that sensor yet only the one that directs info to the ecu. That could very well be the culprit. The car had a mishimoto aluminum radiator when I bought it that was all sorts of horrible inside(heavily rusted and or corroded) I assume that's not a good thing considering the there was more water than anti-freeze in the coolant when it was drained.