[Dave A.]

Are you sure that no dripping is taking place?? Check that suicide bypass hose underneath the intake runners and see if it's soaked with greasy grime and dripping coolant. Can you smell antifreeze when you open the hood??
What's making you think that you might have a BHG?

 

[Dave A.]

Check the coolant overflow bottle for bubbles while the engine is running. If there's a coolant leak into one or more cylinders, then the cooling system pressure will increase enough to cause the pressure relief valve in the radiator cap to open and allow gases to flow into the bottle. Rev the engine up to a fast idle and see if that causes any bubbles in the bottle.