oh no! its the check engine light

hello friends i need some help, i have a 2002 jetta 1.8T, automatic triptronic. the other day i got a code that said the cooling of the car was the problem. i change the temperature sender from the radiator and reset the computer and three days later what do you know its the same devil check engine light. on top of that i have small insertion on the hose that runs from the Intake to the engine and i would like to know if anyone had this problem whats are the dealer charging to change that hose, and what are the side effect from not changing it at an appropriate time cause times are hard.if you can please help. you guys are great!