1998 Nissan Altima Hissing Sound

1998 NISSAN ALTIMA
122,000 MILES • 4 CYL • 2WD • MANUAL
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GALLOWS27
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  • 2 POSTS
I have noticed that when I turn on heater or A/C. the moment I turn the dial up to increase air flow (left hand dial 1 thru 4) a short hissing sound can be heard from the undercarriage of my vehicle. In warmer weather it happens much more frequently and sometimes during acceleration. I do lose engine power, but very much. I was thinking that a valve needs to be replaced, but would like to have a starting point.
Dec 15, 2007 at 12:44 AM
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MHPAUTOS
  • CAR REPAIR CONTRIBUTOR
  • 31,937 POSTS
Hi there,

This will more than likely be a vacuum leak, you will have to check around the engine for vacuum hoses that may be loose, split or disconnected.

Mark (mhpautos)
Dec 15, 2007 at 1:47 AM
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