1997 Camry. Car has a hot smell, radiator is full,

Oil filter? Is it on tight?

Coolant is oil based. The oily mess in the overflow could be very old coolant. Or it could be engine oil from a leaking head gasket.
The rusty stuff on the floor inside the car could be from a leaking heater core.

For this types of problem,check the help link provided below.Click the link below to go through its troubleshooting procedure:-----Antifreeze leaking from front of engine near Air intake? http://technoanswers.blogspot.in/2012/02/antifreeze-leaking-from-front-of-engine.html
----------Antifreeze leaking from freeze plug on throttle body? http://technoanswers.blogspot.in/2012/02/antifreeze-leaking-from-freeze-plug-on.html
---------How to locate the vacuum leak? http://howtobyme.blogspot.in/2012/01/how-to-locate-vacuum-leak.html
-----------How to Perform Car AC Leak detection Test? http://repairhelpcenter.blogspot.com/2011/11/how-to-perform-car-ac-leak-detection.html
------------Common Causes of Car Oil Leaks? http://schematicsdiagram.blogspot.com/2011/12/common-causes-of-car-oil-leaks.html----------- Troubleshoot Car Oil leak? http://schematicsdiagram.blogspot.com/2011/12/troubleshoot-car-oil-leak.html
-----------The plastic housing which goes to the upper radiator hose is cracked and leaking?

http://schematicsdiagram.blogspot.com/2011/12/plastic-housing-which-goes-to-upper.html

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Radiator leaking? http://repairhelpcenter.blogspot.com/2011/12/radiator-leaking.html
-----------This will help.Thanks.

the water leak could be the AC ?? if its on ,if still overheating then ask a local mechanic to advise ast it couild be a multitude of different things causing the engine to run hot ,like a build up of corrosion in the cooling system clogging the rad up .All vehicles must have antifreeze in all year round

is the heater-core inside the car on the passenger side leaking.you can check the inside of the firewall, on the passenger side.

That is coolant leaking and it must be coming form the radiator or hoses, hopefully. You will have to get under the car and trace the source of the leak to be able to formulate any sort of a fix. You are more likely to see the leak when the engine is hot and the system is under pressure. If you do not see anything, It could however be a static leak and will only show up on a cold engine.

I have had a similar problem with my son's Accord. You are lucky that your son knew to stop immediately, this happened to my son and we ended up having the head rebuilt.

A leak may exist but not show up until there is adequate pressure or, you may have a blockage that caused excessive pressure.

We once had the radiator leak which was nearly undetectable in his Accord, check for moisture in the trough where the radiator sits by looking down the inboard side of the radiator with the hood up. You may need a flashlight. Radiators are available at auto parts stores for about $100 and easy to replace. Replace the thermostat, cap and as many hoses as you can at the same time.

Another problem we had was the radiator cap had come apart and leaked periodically.

If the thermostat stuck, this could have caused a temperature and pressure surge explaining the now-you-see-it-now-you-don't leak. A faulty fan, or fan switch could also cause a periodic temperature surge.

The leak could be coming from the thermostat housing which is on the passenger side of a 4 cyl engine, or from the upper or lower radiator hoses or the two heater hoses. The water pump is on the drivers side and connects to the thermostat housing through a metal pipe with O-ring seals.

Drain radiator by opening drain plug. Undo clamp and remove radiator hose from front of engine near oil filter. Undo bolts holding the thermostat housing. Replace. Be sure to use new O-ring. Re-attach the hose. Refill the radiator through the cap. Idle and check for leaks. Cool down and check coolant level.

It sound like there may be a small leak in the cooling system. You can check this by pressurizing the cooling system. You can buy a pressure checker for about 100 dollars. It will usually show up leaks that are small because you can pressurize the system cold and it won't evaporate.

If you notice a 'sweet' smell, or windows tend to fog up, it's your cars heater core leaking. The heater core is located under the dash, passenger side, it's like a mini radiator. The cars cooling system directs hot coolant to it so you can have heat. To change it is an involved procedure.
If there is no evidence of the anti-freeze smell or windows fogging up, and u have been using your air conditioner, it would be a blockage in the drain tube from the a/c. The end of the tube is located under the car on the passenger side , behind the front wheel. The blockage needs to be removed, and will solve the problem. Let me know what u find Curt