The larger one that connects to the valve cover. It seems the noise is coming from where it connects to the valve cover. Seems this hose is a random one a mechanic put on, so I'm ordering one from AB.

 

If I remember correctly thats the PCV hose. Check this thread: https://landroverforums.com/forum/di...4x4-mod-92942/ . As far as what that hose is and it may help you find exactly where it is leaky. This thread is also a sticky.

 

easier and cheaper to just get the right diameter hose from the parts store than order one for the PCV. spray soapy water on the hose to see where it's leaking exactly. the issue might not be the hose..fire the parts cannon at your will but most of us try to avoid it as much as possible.

 

Vacuum leaks are best pinpointed with smoke (e.g. a cheap cigar). Only need to disconnect the fan belt and run for a few seconds, otherwise the fan blows the smoke too much. Some folks use carb cleaner spray to see if engine speed changes. Soap bubbles will work if pressure is applied (e.g. shop blower).