Hello I have a VT 5.7 A4 and i opened my bonnet and i found i cut line at the back of the engine as you can see in the pictures below but I couldn't figrue out what it was so can someone please tell my what it is ? and sould i fix it? and is it important for the engine?
It is the PCV hose and is important. Is you car idling high and is the engine warning light on? A new hose assembly will cost around $70 or you can buy a brass Y piece and the right size hose and just repair the broken part but it probably won't be long before other parts of the hose perish as well.
It allows the crank case fumes to be drawn into the intake manifold and exhausted through combustion. If the hose is broken, the fumes will escape causing pollution and it will also cause your engine to idle higher than it should.