Thanks a lot, head gasket, waterbody, radiator and thermostat are throughly got checked, still it is overheating, I got the number of your mechanic, I will get checked but I have noticed that mechanics don't certainly know the root cause of problem they do random things and after spending a lot of money they will advise to change the assembly, logically if all components of cooling system are okay and lubricating oil is up to max level and recently changed then what is that we are missing???