I have a 1998 Hyundai accent, and whenever i come back from a long trip, and i turn off the car i hear water boiling in he radiator and see vapor comming out of the plastic bottle. The thing is, the car doesn't show signs of over heating and the temp. sensor gives the right temp. and i changed the radiator cap. What could the problem be? what should i do?
Looks like you discovered your own problem. You said....'water boiling'. Water is boiling obviously. Shouldn't be the case. Seems as if somehow the coolant/water mix is off. Drain block and reservoir and refill with 50/50 or 70/30 coolant/water.
I had the same thing... I needed to change one of the large blue 20A fuses
in the fuse box, which likely controlled the rad fan.