Yes, there is an "O" ring inside the fittings.
Drain about 1 gallon of coolant from radiator Remove housing at engine end of upper radiator hose Make note how thermostat is installed Clean both surfaces Install new thermostat and gasket Re-fill coolant slowly to prevent an "airlock" Start engine and watch for leaks Run engine to normal operating temperature with heater on Check coolant level
no
Probably a blown head gasket
Blown head gasket.
Probably a bad head gasket.
Stuck closed thermostat or a bad head gasket.
You have a blown head gasket or a cracked head.
blown head gasket
Blown head gasket - warpped head - or both.
The engine will run hot. This could lead to a blown head gasket. It may even build pressure and cause damage to the radiator and or hoses.
This is caused by a blown gasket that allows coolant to escape. Does your engine smoke sometimes when theirs coolant? If yes, then it's definitely a blown gasket.
It could be a head gasket or cracked head. With the engine cold, take the radiator cap off and crank the engine. If the head gasket is bad coolant should shoot out of the radiator. 12 inches to possibly hitting the hood.