VP. Gushing noise coming from behind the dash.

[jackamole]

Some times while im driving my VP a sound that resembles gushing water comes from what sounds like just behind the dash.
Any thoughts on what it could be?

[needwork2-4fillhabbit]

Its a air bubble in you heatercore. Just need to bleed the system, theres a few threads on how to do it.

[Pub247]

basically to bleed it have the heater on full hot and bring it too operating temp then fill and bleed system correctly