Valve cover breather?

[Tyler Valo]

Where do these mount on a 3.8 and what do they do? Advantages and disadvantages? thanks

[matt3989]

they mount in the spot where you add oil (i beleave) they are not nesseccary unless you are making serious power particulary with FI, im not exactly sure what they are for but i think they help keep the air pressure stable throuhgt the engine

[cam98aro]

they let the valve cover breathe.

there are no advantages or disadvantages really... at least i cant see any.

[grayman]

you don't need a breather unless your turbo or super charger is putting out solid PSI into the engine. At that point you use a breather (along with modding the PCV system) in order to vent the 'positive' pressurized gases more quickly so that you do not blow out seals and the dipstick, etc.

some high compression motors need vented beathers as well.

a brather is not needed on an otherwise 'normal' (lightly modded) L36