Following and over heating incident. I have sytematically taken the following steps to remedy the problem. Replaced stat, replaced cap, had shop replace head gasket, had radiator removed and cleaned when shop said that was the problem. Evacuated air from system. nothing works. Somes times i can idle in the driveway for 20 min no problem, but leave the neighborhood and your stuck. It seems the top radiator hose gets hard when it overheats? If i did not replace it i would think that was blocking the flow. Does anyone have any input that would help?

 

Sound like exhaust gas in the coolant. A simple chemical test (about $60 bucks from parts store, it changes color when it senses products of combustion in the coolant) is in order. It can be used to "prove" that head gaskets are working after replaced, and while it may be a bad install of the head gaskets, or failure to "plane" the heads flat (any machine shop work or the head gasket job?) - it could also be cracked block or cracked head. When heated to a certain point and stressed, the crack opens and allows this type of thing to happen. There is a pressure test that can be done on the block, this is usually done when the engine is taken apart. Not what you wanted to hear with holidays coming.

Please note: the shade tree method of last ditch repair would be a container of KSeal. May work for a while. Because you have a cleaned out radiator it should not cause any additional problems.

You can also attach a scanner to see engine temps in digital form, that way you can see improvements or not before gauge even starts to move off center.