Polo - Land

Il faut regarder en haut de cette page internet en dessous de Polo land et tu auras la réponse.

The sound you are hearing is air leaking across a damaged gasket or a warped sealing surface. With the throttle closed, or in deceleration mode, the manifold pressure is very low and if there is a leak anywhere in the induction system that should normally be sealed, you will hear the (very common) whistle.