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Squealing Noise when Accelerating

22K views 19 replies 11 participants last post by  maladezo 
#1 ·
So i think this is a belt issue...but here's the deal, and this was not happening yesterday. If i rev the motor while parked, or when I accelerate from a light or stop sign, there is a loud squealing noise...if i am idling, the noise stops. if i let ease up and let go of the gas pedal while driving, the noise stops, and then i hit the gas again, and half the time it does not continue, half the time the noise comes back.

how can i diagnose if this is indeed the belt(s) and what can be done/should be done to stop the noise?
 
#2 ·
In addition, if it helps..i only have one belt, and it is turning the alternator, fan and drive pulley. Shouldn't there also be an idler pulley, which is what tensions the belt? or is my alternator the tensioning pulley? the drive pulley and fan pulley also seem to have been swapped for billet/chrome ones..photo attached.
 

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#5 ·
Cute. :)

V belts do not typically use a tensioner, that's a serpentine belt thing. V belts are not as sensitive to tension as flat belts, but of course there is a limit. Your setup is exactly correct OEM. The alternator is the tensioner, by loosening the upper and lower bolt you can swing the alternator outward to increase belt tension.
 
#6 ·
Please note that once a belt starts to slip and squeal it gets a glaze or polished surface on the belt and tightening may not help. At that point you will need to replace the belt.

Rick
 
#7 ·
DL,
It may help to less us know what year/engine you have. Same for your post with the jury rigged/dump-on-the-ground PCV.

Paul
 
#10 ·
Although from your description it seems like the belt is your problem you should 100 percent verify that the noise is/not in the accessory drive - belt and/or accessories (ie alternator, water pump) by removing the belt as suggested by Pony Gaz. If the noise goes away then you need to determine if the issue is in one of the accessories or the belt itself.

If the issue is the belt then there are several things that can cause that including inadequate tension, pulley misalignment, worn belt, or incorrect belt size. For a stock setup your alternator-water pump-crankshaft belt should be 41.2 inches long and 15/32 width (Ford C4TE-8620-S / Motorcraft JB-412). Belt tension can be hard to gauge. When pressed on you should have no more that about 1/2" deflection in the middle of the longest span between pulleys. To check pulley alignment use a long narrow straight edge.

Good luck
Paul
 
#15 ·
Paul hit on all the specifics but one more question.... "Do you have a stock, or a high output alternator?". Have you had your battery load tested. A high-output alternator can drag enough on a v-belt system to cause slippage, especially if it's trying to keep the charge in a weak or failing battery. A water pump with bad bearings can also cause a belt squeal.
 
#18 ·
Can't believe we got to 15 before battery charging/alternator load was brought up!
Pay attention to bartl!!
 
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