A few wks ago my 5.2 overheated. Think it may have been low on coolant. Filled radiator, it was blowing cold air from the vents. Replaced thermostat, still cold. Burped it, then had hot air for about 30 sec.. The hose from the radiator to block is compressing.. Vacuum somewhere. I don't get what it is doing or what is wrong. It hasn't overheated since. But it's hardly getting up to 195 for the thermostat open. I'm very lost....

 

When the motor has ben running for a few min's did you feel any of the hoses under the hood to see if any of them are warm or hot or cold,,,

 

Yes they do get warm. and when you open the radiator you can hear the air go in and the hose goes back to shape. I haven't flushed the heatercore yet.

 

hows the coolant level in the overflow reservoir? there is also the possiblity of a blockage in the overflow line going into the reservoir which could be causing an issue

 

It looks like the overflow tank has a leak.