Did you replace the thermostat and ECT yourself?

Issues could be radiator cap, coolant pump, radiator, thermostat, exhaust gas leak.

Inspect, test or change radiator cap.

 

Changed the Radiator cap and the engine is working good with no over heat. But every two days I need to top up the coolant in the coolant tank. Some time its level coming below the minimum level. I am living in Texarkana TX which is hot in the summer. Is it due to the hot weather or the faulty head gasket? Please let me know.

 

Weather will not cause coolant lose.

Do a block test for exhaust in coolant.

Add die to the coolant and pressure test to check for leaks.

Pull the spark plugs coils/wires to check for coolant in the spark plug tube.

 

Yeah, I really suspect your head gasket is smoked, get a compression test done.

 

I found the issue. Its due to leaky radiator. I am going to change it soon.

 

Happy to hear! Much better than a headgasket!

 

My son bought a 1998 V6 Camry in 2021 with 200,000kms and I noticed that the temp gauge was always reading low and sometimes quite low if for example driving on the freeway on a winters evening. It would sometimes after say 30 minutes of driving idle low to the point where it would almost stall. Looking at the top radiator hose I could see that it looked "puffed" and was under high pressure. This is a sign of a potential blown head gasket. I'm guessing the previous owner (or his mechanic) decided to remove the thermostat to alleviate a cooling system over pressure and overheating condition. Otherwise the car drives fine but probably will never take it to the snow as I don't think it would run very well in an extreme cold situation (we live in Sydney Australia where winters are quite mild). Even in summer the temp gauge never quite reaches normal. I think you may have to resort to what we have been doing and that is running without a thermostat. You could also try putting a lower pressure radiator cap but be prepared to top up the radiator reservoir regularly.