hi ,Ihave a 4trak,petrol engine and it has been overheating,i changed the radiator cap and it seems to be better,i went to change the thermostat,but when i took the housing off there was no thermostat in there,im just checking ,would the thermostat be in the housing at the end of the top radiator hose on the engine,if theres no thermostat,why would this be?,and what damage would this do to my engine,many thanks truewhite0