If they are more than 5 years old I just cut them off and replace them. Hoses get old and brittle and if they let go on the road they can cost you an engine.
drain the radiator down below the top hose and unhook the hose from the radiator and the engine and pull the hose off.
Drain off the radiator coolant into a clean drain pan. Loosen radiator hose clamps. Remove radiator hose. Install in reverse order.
More than likely, the thermostat is stuck. The thermostat is a valve that is supposed to allow water from the radiator to flow through the engine block. As the temperature rises, the thermostat opens and water from the radiator flows through the engine block and draws off heat. If the thermostat is stuck closed, the water cannot flow, no matter how hot it gets. The pressure builds and the upper radiator hose can expand to a point. Eventually the hose will rupture. Have an experienced mechanic replace the thermostat and the hose.
you have to take that bottom radiator hose off to replace it
Follow the top radiator hose back to the engine. The radiator hose connects directly to the thermostat housing. Pull the two bolts that hold the housing then you'll need to work at it to get the housing off since it's stuck on with gasket sealer.
I would just leave it alone. Remove the lower radiator hose to drain and flush the radiator. You don't really need the petcock.
1. Open the radiator cap. 2. Disconnect the top radiator hose. 3. Run the engine for a couple of minutes with the hose off. 4. Insert tap water hose into the radiator where the top hose should be. 5. Run water into the radiator until clear water comes out of the radiator top hose. 6. Continue idling the engine, remove the tap water hose from the radiator, shut off engine as soon as the water stops coming out of the top water hose of the radiator. 7. Reconnect top water hose and fill radiator with antifreeze. Start engine and top off antifreeze.
Thermostat stuck closed.
SLIDE OFF THE LOWER RADIATOR HOSE AT THE RADIATOR...
I usually pull off one end of the lower hose if the radiator petcock is hard to get at or stuck; it is usually easier and it is much faster in most cases.
"Sounds like the thermostat is stuck open." Did it used to?
Drain the Mercury Tracer radiator into a pan. Loosen the clamps at the ends of the radiator hose. Wiggle the hose to free the ends. Slide the hose off and replace it. Tighten the clamps an refill the radiator. Dispose of the old antifreeze as it is toxic to animals.