Why is my car over heating?

Ok I have a 1995 toyota corolla "japanese version" recently I had my engine head repaired I got a New head gasket, New Radiator, new water pump, new thermostat, new radiator cap, I even replace all of my hoses. When the car was completed it was running excellent but after driving it for a while, it will start making this rattling sound like its running hot, but when I stop and I check the car everything seems to be fine the radiator has coolant, the hoses are not leaking coolant I mean the car isnt leaking coolant at all even My fan was working fine, so what I did I take out my thermostat and I didnt put a one in after I did that I didnt hear the noise no more but two days later while I was driving the noise came back again and it will only make the rattling noise after I drive the car for an hour? I juz dont understand? Could my engine head be causing all this trouble?