hissing noise when i turn it off

2006 CHEVROLET TAHOE
155,567 MILES
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BOBBYBUCKMAN
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I have a 96 tahoe lt 5.7 and when it warns up even if im not running the air it makes a hissing noise but it stops so fast i been having trouble finding it but a friend said it sounds like it was coming from the k&n airflow
Aug 22, 2012 at 5:23 PM
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DRCRANKNWRENCH1
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A hissing noise sounds like there is pressure letting off when you turn the truck off. I would replace the radiator cap and see if that does not get rid of it as they lose their ability to hold pressure, which goes up when you turn the truck off, and will lose pressure whcich can eventually lead to overheating.
I cannot think of anything off hand that would sound as if it were coming from the intake tract.
Aug 22, 2012 at 5:41 PM
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BOBBYBUCKMAN
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About a month ago i replaced the old cap with a new pressure release on it but it could be s bad cap. and i just got it out the shop the tech put a new intake gascket and water pump on it and im consantly looking under the truck for leaks amd its not leaking. so im gonna do like u said and get another cap thanks
Aug 22, 2012 at 5:55 PM
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DRCRANKNWRENCH1
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Your very welcome. I hope it works out.
Aug 23, 2012 at 5:23 AM
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