HVAC vacuum leak? [Archive] - GrandAmGT.com Forum


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04-01-2008, 03:30 PM
I bought my car in Jan so this is the first I've run it without the heat on.

When I have the temp control knob set to cold (A/C is not on) and I accelerate I hear a whistling from behind the center dash area. It gets louder as rpm's increase. I do not hear it when idling or when I turn it to hot. I know because the HVAC controls are vacuum controlled it is possible to get a leak here and cause a hissing sound but would it only happen when the knob was turned one way?