I have a 2000 toyota camry Le, 2.2L, 4 cylinder. Recently I have been having some overheating problems with my car. I have been doing a rather extensive amount of research at to what my problem could be, and these are my attempts to fix the problem.
First: Noticed that when idle the engine temperature needle begins to climb after a decent amount of time on the road (2 - 3 hours around ~2000rpm). And eventually red lines if not tended to.
Second: This does not occur while driving, due to free flowing air passing through the radiator. This leads me to believe that there is no blockage within my radiator.
Third: I have been able to remedy the situation by turning on my heater at full blast to pass air through my heater core and cool the engine. And also when I turn my A/C on to force the radiator fans to turn on and cool the radiator.
Fourth: Radiator fans do not turn on automatically when the thermometer needle begins to climb past halfway.
Fifth: I am able to force the fans on by disconnecting the thermo/fan switch, which connects to the coolant temperature sensor on the bottom of my radiator. But when it reconnects the fans turn off.
Sixth: I have changed all included:
relays to both the fans,
master four pronged fan relay,
ECT sensor/fan switch on bottom of the radiator,
ECT sensor on outgoing coolant near engine and next to thermometer,
Flushed and replaced coolant at least three times now.
I have no idea why my fans won't turn on automatically and why my engine continues to overheat. My last possible hypothesis could be that I have a short in the wires somewhere. But wouldn't that keep the fans from turning on entirely?
It's overheating because the fans are not turning on. Why they aren't is another question. You have basically replaced everything. Have you checked for power to the ECT switch at the bottom of the radiator? That is what sends the signal to the PCM to energize the fan relays and turn the fans on.