yeah, loose pump belt or bad pump. also, you may have pinhole exhaust leak into coolant, raising its temp, which is headgasket failure.
with engine running, t-stat open, peek inside the radiator filler neck (ha-ha, you might as well leave it open, so many times we tell you to do this) and check if there's no gasses or foam looking substance present in coolant.
partially glogged radiator, as in inside the radiator.
I am assuming, you use only original coolant and DID NOT have any aftermarket coolants added? some don't mix, you know.
I am not sure I understood the temp switch function. The fan DOES NOT kick in after 197 degrees? and it should, I assume? toyo? as you have access to all the Toyota wisdom. I don't get it, how it does kick at 195 and does not at 197. something's not gearing right here.

 

Checking The Engine Coolant Temperature (ECT) Sensor
Purpose:
The Engine Coolant Temperature (ECT) sensor element extends into the coolant passage where it maintains constant contact with the engine coolant. The Powertrain Control Module (PCM) uses this sensor to measure the temperature of engine coolant.
Operation:
The PCM sends out a reference voltage of approximately five (5) volts to the coolant temperature sensor. As coolant temperature changes, the internal resistance of the sensor will change, causing a varying voltage drop across the sensor. The PCM reads the voltage drop across the sensor as engine coolant temperature.
Based on the amount of voltage drop at the coolant sensor, the PCM will, adjust the fuel injector pulse width (a cold engine will receive a longer pulse width, allowing for a richer mixture), compensate for condensation of fuel in the intake manifold, monitor and adjust engine warm-up speed, advance ignition timing when the engine is cold, and activate the Electric EGR Transducer (EET) to prevent vacuum from reaching the EGR valve.

Coolant Temperature Sensor Resistance Test:

1. With key off, disconnect connector from coolant temperature sensor.
2. Connect ohmmeter across coolant temperature sensor. Resistance should read as follows;
   • 700 to 1,000 Ohms at approximately 200�F (operating temperature).
   • 7,000 to 13,000 ohms at approximately 70�F, (room temperature).
3. If resistance is not within specifications, replace sensor.

As always, check the service manual for the proper procedures and specifications for your particular vehicle.

 

As the radiator needs to be removed if you have the money replace the fan temp switch, ditto for the gauge sender.

Rockauto.com has parts at reasonable prices.

 

Thanks guys for the input.

Wow, I have to pull the rad to replace the sensor? That's more than I hoped to do. Oh well....

Regards, Brenden.

 

Auto Repair: Coolant Temperature Sensors - Testing and Replacing - YouTube

2001 Toyota Camry 4 cyl gauge says its overheating? - Yahoo! Answers

you do not need to remove radiator to replace coolant sensor.

| Repair Guides | Coolant Temperature Sensor | Testing | AutoZone.com

also, make sure, like it's said in link 2 at the very bottom, that your thermal fan switch is working.

 

2001 Toyota Camry Problem Start

there's diagram showing coolant sensor. it's #7.

radiator removal? riiiiiiiiiiiight...

 

Thanks for the links. But it did raise a question; I thought the sensor was located on the bottom of the radiator on the passenger side? The diagram seems to be pointing to the top of the engine. Are there two sensors?

Regards, Brenden.

 

The one on the bottom of radiator is the switch for the fans.

The ECT and sensor for temp gauge are on top.

 

Ah.....

I need to get my nomenclature straight.

Thanks, Brenden.

 

Okay, well here's an addendum; I noticd today that while driving at highway speeds going uphill, the car's temp gauge went to the 2:30 position. When I went down the other side of the hill and coasted, the temp gauge dropped back down to the 4:00 position. I also noticed that while the fans turn on when I start the AC, they cycle on and off every 20 seconds or so. Is that what they are supposed to do? I know that's what they are supposed to do without the AC on, but I thought they stayed on with the AC on?

When I flushed the rad I didn't notice any gunk even in the backflush, but the hose did fill the radiator and it backed up, athough the stream was heavy at the drain. Not sure if this is a fail on Joey's hose test. I started thinking that maybe there is a lot of funk in the rad and that maybe this is also on the sensor and that's why the fans don't turn on as well as why the engine runs hotter when stressed. Thoughts?

Regards, Brenden.