Thermostat bypass pipe
 

I have a 2002 Chevy Silverado 2500 HD with approx 160k miles on it. I noticed a coolant leak at the top, front of the engine. Immediately under the thermostat at the top of the bypass pipe there was a leak. I ordered a new pipe, was unable to get the new pipe properly seated, therefore placed new gaskets on the old bypass pipe as this was the actual issue. Still have a leak. Has anyone had this issue? If so, how was this fixed? I cannot find a single thing about bypass pipe leaks or how to replace them. Any help greatly appreciated.