First post. I'm sure this is covered someplace. Just now diving in...

My HCV started leaking. Replaced. Still leaking. Then replaced hoses. Same. No prior issues. Anything that could cause this issue besides a faulty "new" HCV?

Car is an 87' z28. 305 tpi.

Thanks.

You had a leak, you've replaced every piece that could possibly leak and now there's still a leak. There are 3 possibilities - The leak is somewhere else (like the throttle heater hose?), or one of the hoses isn't clamped straight, or the valve is leaking because it's defective (unlikely) or one of the or plastic nipples got crushed by over tightening a hose.

I was wondering what else, if anything could be a potential cause. The only leak is at the valve? If nothing else will do so, makes me suspect the HCV.

Where is it leaking from? Are you using the screw type hose clamps or the spring type? Maybe the heater core could be plugged up causing high pressures?

Update. All new hoses.two OEM clamps, the other are standard clamps.

Installed new cap on radiator tonight. Here is what I now know....

Valve purges.... Still. AC off, turned bottom temp lever to heat..., no leaky