# 97 Sentra Whistle/Squeal from engine near belt



## R2d2 (Nov 3, 2007)

97 Sentra GXE 1.6. Whistle/Squeal coming from engine, near the belt. Sound present when car is moving or stopped. Sound loud enough to be heard from the driver seat or when outside even with the hood closed. The sound comes and goes when driving, but most of the time stays there. Sound is prominent when accelerating. Sound goes away when car is idling and the engine is cold. Sound stays very audible when the car is idling but the engine is hot. Sound is prominent when the engine is hot. 
108k miles. Serpentine belt looks good. Serpentine belt changed less than 4 years ago at 85k miles.
I can post a MP3 or video file with the Whistle/Squeal sound if necessary.
Is the pulley or the belt? How can I diagnose?


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## jdg (Aug 27, 2009)

Get a can of "belt dressing", spray a little bit on the belts, listen for a change in sound.
4 year old serpentine belt could easily have gone south depending on the crud that gets splashed up on it.
My bet is a bad idler pulley though.


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## smj999smj (Jan 1, 2006)

I don't recommend belt dressing. Spraying soapy water with a spray bottle on the belt can help determine if the noise is coming from the belt or the pulley. You could have a bad bearing. Or are the belts in need of adjusting?


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## jdg (Aug 27, 2009)

Well, neither do I, no more than I'd recommend Fix-A-Flat (ewww), but ya know how it is...


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## always_shifting (Mar 1, 2012)

take off your belt, but before you go and get a replacement, check all your pulleys. especially your idler and AC (if you have AC). if all of those spin freely and don't grind or squeak, then just get a new belt.


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## R2d2 (Nov 3, 2007)

Thanks for your messages. Is there a way to diagnose this without taking the belt off? I have never taken the belt off myself.


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## thxone (Feb 7, 2012)

Actually what you have is a pulley bearing that is shot. Metal expands when hot and contracts when cold. When your car warms up the friction from the belt causes heat, the pulley rotating causes heat and the engine will transfer heat to your pulleys. This will and does cause a squeal or chirping from a bad pulley. Could be alternator, could be a tensioner... narrow down the direction of the noise, isolate the pulley and repair or replace if possible. Just trust me.


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## always_shifting (Mar 1, 2012)

the belt isn't hard to take off. just loosen the idler pulley and then you can just fidget the belt off.


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## smj999smj (Jan 1, 2006)

Nissan put out a TSB that's a great tool to identify the source of belt noise. You can find it at this link:

http://ww2.justanswer.com/uploads/Speedytimzalez/2010-10-13_204138_wergewrgwerwrewg.pdf

Also, there should be two belts. One drives the water pump and P/S pump and the other drives the alternator and A/C compressor (or just the alternator, on non-A/C models).


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## R2d2 (Nov 3, 2007)

How many belts are on a 97 Sentra 1.6L automatic with Airconditioner?


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## lukesSX (Feb 17, 2010)

Pretty sure there are 2.


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## R2d2 (Nov 3, 2007)

If one is the serpentine belt, what is the other one for?


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## lukesSX (Feb 17, 2010)

One goes to the crank, water and power steering pump, and the other goes to the alternator, crank, and a/c compressor.


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## R2d2 (Nov 3, 2007)

*Did the soap-water test*

I just did the soap water test. When I spray soap water on the belt (belt #1) that goes over the water pump and power steering, the high pitch noise goes away. It comes back after a few minutes. I spray again, and the noise goes away again for a few minutes. But, whenever I rev the engine the sound comes back and for a second or two.
When the sound was gone after spraying on belt #1, I sprayed some soap-water on the other belt that (was quiet before) goes over the alternator, air-conditioner and that belt started squealing.
Is the culprit belt #1 or the water pump pulley (it got very wet from spray)?



smj999smj said:


> Nissan put out a TSB that's a great tool to identify the source of belt noise. You can find it at this link:
> 
> http://ww2.justanswer.com/uploads/Speedytimzalez/2010-10-13_204138_wergewrgwerwrewg.pdf
> 
> Also, there should be two belts. One drives the water pump and P/S pump and the other drives the alternator and A/C compressor (or just the alternator, on non-A/C models).


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## Jopet (Aug 10, 2009)

here's a video on belt chirp. It's not a sentra but most of the information is helpful


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## R2d2 (Nov 3, 2007)

Thanks for the video. I re-performed the water test and this time the noise did not go away.


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## lukesSX (Feb 17, 2010)

You could check to see if it's one of your pulley bearings. I usually use one of those car stethoscopes, but I'm sure there are other ways to do it.


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