Kia Sedona overheating?

It can be faulty thermostat .But in your case its replaced.-------------

After replacing thermostat, bleed the cooling system . You would top off the coolant after replacing the thermostat start the engine and let it run until the cooling fan cycles 3 times. Have a drain pan under the vehicle to catch any coolant that comes out. Turn the vehicle off install cap and see if there is still an issue. If there is then you are going to need to have the head gasket checked along with the head to see of there are any cracks.

It can be worn out radiator cap check it.
It can be coolant leak issue.
Check behind the dash and in the boot for leaks .
Also test for exhaust fumes in the radiator (i.e. head gasket) .
The oil level should be proper.
The radiator fan should also come on. if not then , disconnect the fan sensor. With sensor disconnected fan should run permanently.Once the sensor terminals are shorted/ jumper together.

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It could be possible that the water pump is failing.The blades of the water pump impeller may have come free/loose from the shaft.

First off, did you check for air in the system? I still think this is a viable diagnosis.

But if you have,m then its faulty head gasket or blogged head gasket.

The good news is that if you do not have coolant in the oil or vice versa, your cylinder head gasket is good and you do not need to remove the heads. One way to check the water pump theory is to start and run the car to operating temperature with the radiator cap off. You should see the fluid swirling at the top of the radiator and moving through the system if the water pump is working. If not then water pump is faulty and causing over heat.---------

Also check the hoses.If any of them is blocked.It can cause the problem too.---------