Have you used Head Gasket Sealer ?

Ive used it on a few vehicles and have had varying results.It depends on where the head gasket is blown and how dictates if it will work. It has worked more than half the time though. You said there is a temperature differential in the radiator though? If its hot on one end and cold on the other you may have a restricted Radiator or faulty water pump causing low coolant flow. What kind of car is this?

U seem 2 b saying that there is a difference in temp between the in-flo & out-flow hose,if this is the case,U more than likely have a stuck thermostat,all cars have a bypass and allow a small flow at all times.U can easily determine this by removing the thermostat & heating it in a pan of water.If the water boils and it still hasn't opened fully, it's bad.If u have a blown gasket it will gurgle air into rad.-blow water out tailpipe-r have coffee-cream colored oil on dipstick.If u do have a blown gasket Sodium Silicate { liquid-glass} is the only thing I know of to repair cracked heads r blown gasket,without pulling heads. 1st check the oil-2nd remove the rad. cap, 2 see if all conditions r met, if not allow it 2 cool & remove thermostat.At NORMAL operating temp. there won't b a discernible difference in the temp of the in & out rad.hoses,IE u won't b able to keep ur hand on either 1. good luck