Cold radiator i have the same problem. the car is over heating anr the radiator is only hot in the top corner. im told it is the thermostat. not opening i think so am gonna try.

Have you checked the thermostat in the cooling system? When was the coolant last changed? Old coolant can collect dirt and clog up areas of the engine and radiator.
A thermostat is a simple valve the open when it gets hot and closes when it cools down. One that is old or sticking can cause overheating as it doesn't open and let the coolant flow through the radiator to cool it down. They are usually not very expensive and not a difficult job to replace.
A simple first check is to use the top and bottom radiator hoses. This check is easy, uses no tools and only costs the fuel you use to run the engine.
The Top Hose is the largest flexible rubber pipe that connects directly to the radiator, usually on one of the top corners. You will need to put your hand near the engine so BE CAREFUL!
With the engine cold, start the engine and gently hold the top pipe. It should be cold. Let the vehicle sit at idle and let it warm up to working temperature. Every 2 to 3 minutes check the top pipe again. If the thermostat is working after a few minutes the top pipe should start to warm up. it should get quite hot.
After about 15 minutes if the top pipe is still COLD *TURN THE ENGINE OFF!* You possibly have a faulty Thermostat.
If the top pipe heats up you can check the Bottom Pipe to see if it could be a Radiator issue. This is a pipe about the same size as the Top Pipe but it is on the lowest part of the radiator. This can be done with the engine OFF, once the vehicle is up to working temperature, (the Top Pipe is hot). Carefully reach down and grip it just like you did to the Top Pipe. This pipe should be warm but NOT hot. If this pipe is Cold you might need to get the radiator checked for damage or to see if it is clogged.

First check you have enough coolant in the engine then you will need to check to see if your coolant thermostat is working. The simplest way to do this is to check the radiator hose pipes.
***Note*** You will need to put your hands inside the engine bay when the engine and radiator are HOT!!
With the engine OFF open the bonnet and find the largest top hose pipe on the radiator. It should be on one corner high on the radiator.
Start the car and let it idle. Carefully touch the highest large hose at the top of the radiator. It should feel cold. If the thermostat is working that top pipe should get gradually warmer as the engine warms up to working temperature. It will get almost too hot to touch.
If the top pipe stays cold or is only slightly warm change the thermostat and test the same way.

The issue could be an air bubble in the system or a faulty thermostat. If you have had the car out on a trip long enough for it to over heat an air bubble will be less likely. Re-check your coolant level, it will show a lower level if there was a bubble.
A simple test for the thermostat is this. When the engine is cold run it at idle speed until it is at working temperature. This will stop the engine heating up too quickly and will take at least five minutes.
Turn the engine OFF and open the bonnet, (the hood). CAREFULLY feel the large pipes going to and from the radiator. Both should be hot. If the top one is still cold your thermostat is probably faulty.

if I understand your problem the car is overheating with the A/C turned off? u may have a bad thermostat or a blockage in radiator. open the radiator cap when car is cold and start the engine. look into the radiator and see if fluid is flowing if its not that's good it means when engine is cold the thermostat is closed. after the car reaches normal operating temp the stat should open and the fluid flow through the radiator. if this is not the case then replace thermostat. if it passes this test then check the top radiator hose to see if its hot then check the bottom hose it should be about the same temp as the top. if it is cold or just warm then u most likely have a blockage in the radiator. if so u can replace it or have it redone at radiator shop. if radiator is ok then look at heater core. when the engine is warm u should have heat. u can use the hose test here as well. the two smaller hoses that go into firewall to heater should be hot when using the heat if not then there is a blockage in heater core.. hope this helps

Radiator is either clogged,or it's bad. You could also check the heater core.

thet moment stop your engine and grab top radiator hose, feel the heat then grab lower radiator hose they have to be hot same heat. Top hose very hot is radiator blockage, Or lower hose very hot thermostat damage ,for test thermostat tide whith a string or wire have one glass cold water and juck boiling water deep thermostat in and you have to see the opening if is not then you have to replace it. Don ever youse radiator flush with the thermostat on. Blown head gasket means continual air bubble when you remove radiator cap special white froth,check for loose or damage hose and heter leaks when cooling system is under pressure.check low and high rpm exhaust fumes.

The likely problem is an air bubble in your cooling system. Recommend you park on an incline, remove the radiator cap, set the heater on high, start the car and let it warm up until there is flow in the radiator. Fill the radiator and keep it full while the engine continues to run. Look for any bleed ports the system may have either in the hoses or at the attach point housings. Crack any bleeders open to allow any air out. Top off the radiator all the way to the neck and make sure there are no bubbles coming up. Bubbles coming out the radiator are an indication of a blown head gasket. If no bubbles, close the cap. Hopefully this will solve the problem.

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yes this means the thermostat is stuck closed if replaced this and still doing it take it out take back where bought it tell them malfunctioning need another one

Why was radiator replaced?Did it have heat before ? If it was plugged, the heater core may also be plugged. Try flushing it with a water hose in both directions. I dont know why the botton radiator hose would be cold, the radiator should be a uniform temp and the air coming through the radiator should be HOT, when the engine is at operating temp. What condition was the old coolant? if it was rusty, the water pump may have lower flow than normal.

Run the engine and look at the header tank , is there lots of air bubbles coming back out of the water if is then the head gasket may have split and that is down to either a can of Radweld or a strip down repair

If the radiator is not uniformly hot them I would go for that as your problem

Normal operation is that the engine starts the thermostat is closed , engine block heats up and opens water starts to circulate around the block

So to check that you need to fill the radiator with cold water run it for a few minutes check the bottom hose it should be cold

The stat opens and the bottom hose should get hot as the water from the block is pumped into the radiator for cooling.

The radiator should get hot all over and the cooling fan should kick in when the sensor hits the over limit stop.

If that does not happen then get someone to remove the stat altogether (It is only there to get the engine block warm quickly in cold regions )

In which case the bottom hose should go from cold to warm to hot