Hissing air noise from belt area of Chevy S-10

Hello all,
I’m at my wit’s end and financially strapped. I own a 2001 Chevy s10 4.3 litter engine 2 wheel drive truck. Every time I accelerate I hear a hissing air sound like a vacuum cleaner from the belt/pulley areas. I’ve changed the alternator, a pulley, the tensioner, the air compressor, and the power steering pump is only 5,000 miles old. The sound has not gone away. I have no engine overheating or anti freeze leaks and the power steering works fine. When I first changed the power steering, the wheel was super hard to turn and it would sporadically get easier; now it us easy to turn. What could be causing this sound? I rather not change the water pump now. Please help.


You may not have any issue at all actually. The S10 are notorious for EXTREMELY LOUD cooling fans…At least the belt driven fans fall into this category. I noticed this from day one on all of the S10’s, Jimmys, Blazers etc… They ALL have very loud fans. Nothing out of the ordinary there. Now if you are speaking of an actual vacume noise…as in engine vacume…then you have some hunting around to do to find the culprit. Many times its a little vacume hose or the power brake line getting a crack and hissing its head off. Hope this helps.

Can you verify the sound with the hood up and a friend gunning the engine?