What is this sound?

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Anyone know what this pulsing whining sound at idle is? Seems to be coming from near the fan. I currently have the rig apart, will do more investigation when I get it running again, but just wanted to check if anyone knew off the top of their head. Thanks

 
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Where was the recording taken, inside the vehicle or outside, and
near what exactly??
 
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Anyone know what this pulsing whining sound at idle is? Seems to be coming from near the fan. I currently have the rig apart, will do more investigation when I get it running again, but just wanted to check if anyone knew off the top of their head. Thanks


That is your alternator belts. They are worn and not tight enough. Mine has that frequently and it reminds me I need to snug up the tensioner.
 
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Where was the recording taken, inside the vehicle or outside, and
near what exactly??
My spotter took the video outside about 20 feet away or so.
 
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baldilocks

Battle Ground, WA
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Definitely belts. I run Toyota belts only and after a couple years mine began singing the same tune. No amount of adjustment or belt dressing would keep them quiet for long so I replaced them even though they were not worn out. Two years later and the new belts are still quiet. The others reside in my spares box.
 
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Geez, my hearing must be off, all I perceive is what sounds like an electronic hum or whine, nothing like bad/slipping belts IME.

Can the OP get another sound clip closer to the engine?
 
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Geez, my hearing must be off, all I perceive is what sounds like an electronic hum or whine, nothing like bad/slipping belts IME.

Can the OP get another sound clip closer to the engine?
It's kind of a high pitched "yer-yer-yer-yer-yer" sound.
 
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OK, thanks, maybe it's my speakers??
 
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F7B2C44D-1225-4999-9845-0727FE7216CE.jpeg
 
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I've had entire conversations making different noises to get to a proper diagnosis.

Three nights ago, it was with my wife about her van. I am 200 miles away and won't be home for at least another week. She told me the van sounded like it started and died. Then we went through all the different noises and it turns out the van didn't actually start and die, but it never actually started. She had held the starter again.

I laugh when I hear other people do this because I can relate. Make fun all you want, but it works.
 
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@WCBlueSky

Definitely squeeky belts. Start by tightening the belts.

If you can twist the belts by hand enough to see the surface that rides on the pulleys than the belts are too loose.

If tightening the belts doesn't fix the problem than it is time to replace the belts and check all the pulleys while the belts are off.

If any of the pulleys make a noise, feel loose, or don't spin smoothly than replace them.

Personally I change my belts every 3 years or 40,000 miles if for no other reason than peace of mind when I am all alone in remote places.

While changing belts it is also a good time to clean up and maintain the battery and flush the cooling system.

Make sure to save the old belts for a backup and don't break your radiator nipple when you change or tighten your belts.
 
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Belt tension gauge (Gates 91107) shows much lower than the 60-100 ft spec in the FSM, first thing I'll try is tightening the belts. Thanks for the tips. Belts are OEM with less than 20k miles on them.
 
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FWIW one quick way IME to diagnose noise coming from loose/old belts is to take a garden hose and aim it toward the belts for half a second while the engine is running. If the noise goes away then comes back over a couple of seconds it's likely the belts.

Tip: do not stand by the front fenders while doing this (or you'll get a shower).
 
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Giant ants?
 

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