If it hums loud especially right after you start it, check to see if it's coming from the air intake. If it is, it is probably your IAC (idle air control) valve. Some people clean them out with gumout or electronics parts cleaner, but before you spray a lot of cleaner in it, remember that it is an electronic component and it can be damaged. It might be better to replace it if it is indeed bad.
Sounds like the fuel pump is running May be a failed relay
Sounds like a wheel bearing.
sounds like a hole in your radiator or hoses.
it does that because it has a generator which makes the engine makes these sounds
Sounds like you may have a bad head gasket
Sounds like you need a new radiator cap, you can get the cap tested to see if it is holding the rated pressure.
Your thermostat is stuck closed. you will need to replace it. The thermostat controls the circulation through the radiator - when the engine heats up the thermostat is meant to switch circulation from just-engine to engine+radiator. Sounds like this isn't happening.
I know that the top radiator hose on my 4.0 liter OHV gets hot when the engine thermostat opens allowing the engine coolant to flow through the radiator and the bottom return hose connects the radiator to the water pump should be cooler - sounds normal to me but I'm not a mechanic / technician
sounds like a vacuum leak some where in the system
A humming noise on a 1999 Park Avenue is caused by bad wheel bearings. When bearings are loose or worn they will create a loud humming noise that will get louder and louder as the car accelerates.
sounds like a motor mount is broken or a transmition mount. have those checked.
Sounds like a fan or fan shroud problem, but you could also be dealing with a plugged radiator, undersize radiator, or thermostat problem.