Radiator Cap Blows Off, Fissing from water pipe to water pump

[1qwikspyder]

Well after I do a few pulls, my car starts to smoke from under the hood. I'll pop the hood and the radiator cap will be turned loose and smoking. Also, I hear a hissing sound coming from around where the water pipe connects to the water pump. I'm assuming the o-ring is not sealing. If I press on the water pipe the fizzing noise will go away. Could the two problems be related. I've tried a brand new radiator cap but was wondering if getting one with a harder spring would fix my problem.

[95blackGsTurbo]

Is it blowing off at normal temps. or at when you overheat it? Only time I have ever heard of that happening is when you crack a head or blow a headgasket. When was the last time your thermostat was replaced. It could be stuck shut and never opening up causing the coolant to boil and blow the cap off. Try replacing your thermostat first but do a compression check too.

[1qwikspyder]

Head was pressure tested and resurfaced while doing the rebuild on my motor, as well as a new cometic hg. I did a compression test and results came up 175 across the board. The thermostat is new as well.

[1qwikspyder]

o and btw, the car never overheats. The cap blows off and I pull over, put water in, and tighten the cap. It's fine again after that.