Hello, I have a 6.2L "J" vin Chevy P20. The odometer says it has 50k miles. I've had it for about 9months and have been working various issues. It starts and runs with no noticeable white smoke from the exhaust, except on initial start-up and then only a little. Recently I have been blowing coolant out of the coolant overflow bottle. I also noticed that the upper radiator is rock hard after the vehicle warms up. Since ownership (9 months) I've replaced the thermostat, coolant, radiator cap, fuel cap, lift pump, and most hoses. Temps also seem ok(as long as there is coolant) All was fine until recently. I do not see coolant in the oil or oil in the coolant. I need this vehicle to work reliably, so if this is a head/gasket issue, Id just assume to get'er'done now before the problem manifests into something that leaves me stranded. When I bought it, it had the wrong style rad cap on it and would collapse the upper hose.

Thanks!

PS what I keep thinking about is, "what could make the upper radiator hose so pressurized". The only thought I have is the heads/gaskets/ cracks...