Overheating

WTF ,driving home today and POOF!!!! the radiator hose that connects to the engine block(top one) just blew up.....how freakin' embarrasing...everyone was looking at me....if its not one thing its another with my car this year....I just replaced the hose, started to drive and within 15 min. the thermostat just jumped to the red zone, good thing I was not far from home. Anyways, my neighbor told me that since the top hose is hot and the bottom one was cool that means the water is not draining to the lower one and it may be a thermostat/valve problem with the sensor or something...my qusetion is where is this such sensor and will it be hard to replace??? please help.......1998 3.8L automatic