Why does pressure build up in cooling system
 

Hey I have a 2000 Eldorado ESC. Why does my radiator hose get hard? The pressure is causing the coolent to come back out through the hose attahched tothe resevoir cap. It usually spills after the car is turned off. I already changed the thermostat (180 degrees). What else can i do?

RE: Why does pressure build up in cooling system
 

Wrong thermostat, should be 195 to 205F. Coolant cap builds up pressure to raise the boiling point of coolant from approx 212 degrees to about 250 degrees. Check the small by pass hose to the recovery tank to see if plugged up, restricting flow. If not restricted, I would suspect the radiator cap is weak, probably original as well.

RE: Why does pressure build up in cooling system
 

Well I forgot to mention that I already changed the cap, but i do have a question. If the thermostat is suppoesed to be 195-205, then why did the guy at the autoparts storegive me a 180? I'm awful sorry but I forgot to mention that I think my fans are not work working properly. They turn on when the engine starts but then they shut off after around less then half a minute, and I dont think they go back on after that. Whats the deal with that?