AIR JAY

Whats up out there in protege woorld. I was wondering. I have a 1994 mazda protege dx. last year I took it to the mechanic shop because the needle on my temp gauge.;was a little higher than the halfway point. So they replaced the coolant sensor, and the fan sensor. flushed the radiator,and put a new thermostat. This was in the summer when it was hot . I made it about 4 blocks and this time the gauge red all the way on hot,as far as it could go. I took the car back,and he told me the gauge must be bad because he said if youre car was really that hot as the gauge says it would have been pumping it out.Fine so i was satisfied with that answer. I had a friend of mine look at the car and he said something like, the car reads 120 degrees when hot. And that the new cars run hotter than that so he said It was fine. But it still bugs the crap out of me to see it like that. every time I get gas,I open the hood and touch the radiator coolant cap and its hot as hell. Forget about trying to touch it in the summer. Could it be that the cap on the radiator is the wrong one even though it fits. And is causing the temp to go up and down. please help thanks