Recently I got my Liana's Engine Overheating problem even the environment temperature not too much raised. I started to diagnose the problem by my own and feel that the Radiator fan operating too late. Normally the fan must start operating when the water temperature is around 82 - 83?C, where as my car's radiator fan was starting to operate at around 94-95?C, resulting creation of steam and high pressure in whole cooling system. The heat gauge installed in dash board never go up beyond the middle.
I consulted with one of my friend who is electrical Engineer and have vast experience in Thermocouple, Thermo switches. I got info from him that normal thermo switches have a working life of one year and they have to change every year to get accurate information of object temperature. The thermo sensors / Switched used in cars are specially designed for a longer life span, even then the accuracy of thermo switches of cars go down after 4-5 years.
what I did
I managed to buy a brand new thermo sentor/switches for my Liana (Never rely on used or KABLI, as those have completed their life already), replaced the new in Engine and got the problem solved. Now no overheating, no high pressure in cooling system.
So Whenever buying a used car (more than 5 years old) always consider to replace the thermo sensor.