New VW owner

69falcon · Mechanic Joined: Nov 09, 2009 Posts: 45

if the hose is attached to a tube by the oil filler cap it is to vent excess pressure in the crankcase...blow by from the piston rings...on American cars this is the PCV valve and (like Randy said) needs a breather to keep everything else out... but it could be the heated air hose that attached to the original air cleaner to provide warm air on start up...on the old American engines it was a hose that pulled air from around the exhaust and into the air cleaner...a butterfly valve closed when the engine warmed up and it pulled in fresh air Very Happy