coolant only flows through top hose when engine is at normal operating temp.. so u have the wrong thermostat, or no coolant in the rad....
Or the water pump has failed and is not pumping the water.
the hoses leading to and from your radiator might be clogged. If you had a rusty radiator, the rust may have clogged the hoses that carry the coolant. you should check all your hoses and even flush them out.
The top radiator hose is above the thermostat. If the top radiator hose is hot, the thermostat is opening. The thermostat is not the problem. Perhaps the radiator is clogged up or the water pump is bad. Look elsewhere.
Stuck Thermostat, clogged radiator, defective water pump, defective fan, fan relay, or blown fuse. A defective radiator cap will in some instances make the car to appear to be overheating.
clogged radiator, advanced timing, worn water pump, dragging brakes, etc. Usually, the thermostat isn't the real cause of overheating.
it is possible your radiator is clogged
Air in the system. Bleed the system. Defective thermostat, clogged radiator, defective cooling fan or fan clutch.
Possibilities: Cooling fan not working. Low on coolant. Clogged radiator, radiator hose or block.
Low of coolant, defective water pump, clogged radiator interior or exterior, cooling fans not working, thermostat installed up side down, or you may have bought a bad, new, thermostat. It happens. Also running 100% water will cause it to overheat. Run a 50/50 mix.
Make sure your cooling fans are coming on and that your water is circulating through your radiator and hoses are not clogged. You may want to try and flush your cooling system
It could be the radiator is clogged. The thermostat could be bad (prevents the coolant from circulating from radiator to engine block)
It could be a clogged radiator or cracked head or bad head gasket.
If your truck is overheating!!! Then check the upper radiator and lower radiator hose's , if the lower is cooler the the upper the either the thermostat is not opening or the radiator is clogged