I have a 1995 SC400 with 240K miles. The car has been excellent, but is currently overheating when driving. I've changed the thermostat and the car has no visable leaks. The top of the radiator is hot and I'm not sure if the fan is working properly since I can stop it with my hands while the car is running. I also have an occassional strong smell of gas in the inside of the car. There is also no heat. One of the top radiator hoses feels like there is no pressure in it as well. The car runs great with no unusual amount of smoke from the exhaust. I've had the radiator cap off while running, and the coolent is not hot while the guage is very high. Any takers on this one?
Symptoms indicates coolant is not circulating and it could be due to a bad water pump or stuck thermostat. Try removing the thermostat and running engine to see if there are any difference. At radiator cap you should be able to see the coolant circulating if the water pump is good.
With engine off, turn the fan and if there is slight resistance, the fan is good.
If it is a fan problem, the lower hose would be hot as well.
As to the gas smell, it could be the EVAP system or a leakage somewhere which requires visual inspections to locate possible faulty areas.