just had my 84 trans am engine rebuilt wit new block, new radiator, water pump, the works. I drove it an hour today and about 40 minutes in it started to go up in temp. by the time i was 15 minutes away it reached red and then started to overflow when I parked. it didn't overflow until then. I pulled off twice to let it cool a little. the hose was very hard with and i couldn't squeeze it at all but it was very hot. we got another therm. and replaced it seemed to fix the problem. got back home and it stayed at 220 the entire time. pulled in driveway and the fan light was on but no fan now. what could cause the hose to be very hot going to the manifold but not allowing flow or seeming that way since it couldn't be squeezed even while running with the engine temp where it should've opened. i checked the old one and it does still work. it was fine so what could be causing this. thanks for got to tad that both hoses on top and bottom are hot. I checked the feel of the radiator but the engine has been off for 30 minutes now. the top feels warm ad the bottom is cool but again both hoses are hot from water pump and on top.if the car is running lean could it do this? i still have a 305 with 700R4 trans. I have and edelbrock carb and got rid of all the smog stuff since it didn't work. also had to switch to vacuum distributor and not computer controlled anymore.

 

Air pocket from chainging the water pump? I had a similar problem when i changed my water pump.

 

any clue how to get rid of it if that's my problem? thanks

 

On mine, I started the engine with the radiator cap off, and i just kept watching the coolant level. Everytime a bubble would burst, you could see the coolant get low in the radiator. I kept filling it up and watching it untill it stopped. Dont know if this is your problem or not.

 

is the fix. Happened to me too.