Don't use any kind of anti-squeal stuff on serpentine drive belts. That stuff is for the older V-belts. Those work by wedging themselves against the sides of the pulley. They squeal when the belt is worn down to the point it's running on the bottom of the pulley instead of on the sides. There's no grip there.
Carburetor cleaner or brake parts cleaner is often used to clean the chemicals off the pulleys. What likely happened on yours is the chemicals found their way onto the new belt, causing the same problem. You can try spraying a cleaner onto the running belt, but it may need to be replaced again after the pulleys have been cleaned. The other problem is dirt and small pebbles can become trapped by those chemicals and become embedded in the belt. Those won't cause squealing. They can sound like tiny stone chips flinging off and hitting something metal. They usually stick to the smooth backside of the belt. To identify those, very carefully hold the end of a flat file lightly on the belt where it comes around a pulley. You'll see tiny sparks each time a pebble hits the file. If you do that long enough, most of the debris will be chipped off.
First check the spring-loaded tensioner pulley to see if it's holding the belt tight. This should be obvious, but I have to say it for the benefit of others researching this topic, . . . do this with the engine not running. If you can find a good spot between two pulleys, tug on the belt to make the tensioner pulley rotate on its pivot. It should tug back and tighten the belt when you release it. If it doesn't make the belt tight enough, it's rarely due to a weak spring. The common cause is rust or dirt buildup on the pivot. It's common for that pulley to bounce as the engine is running. After a bounce, that rust or dirt can prevent the spring from pulling the belt tight again, resulting in squealing.
Next, look for a pulley that's turned or tipped. This also applies to the tensioner pulley where the pivot can wear, preventing it from holding the pulley straight. This problem causes the belt to slide sideways across a pulley as it goes around it. That's what sets up the most horrible squeals. You can often identify that by dribbling a little water on the backside of the belt as the engine is running. Most often the squeal will get worse for a few seconds, but it is also possible for it to get quieter.
While more difficult to do, try to look down on the belt, and see if it is peeking out a little on one of the lower pulleys. It's not normal to see even 1/16" sticking out to one side. If you see that and it's excessive, either that pulley, or the one right before it is tipped or turned.
The last thing to look for is where the belt is running on a pulley in relation to the paint that has worn off that pulley. Most are painted black, then they'll be shiny silver where the belt has been running. If you see the belt running in a new area, or if the silver section is wider than the belt, that pulley or the one before it needs further inspection. This applies to smooth pulleys, not those with grooves.
You might find more ideas from these articles:
https://www.2carpros.com/articles/chirping-noise
https://www.2carpros.com/articles/serpentine-belt-tensioner-replacement
Let me know if you solve this or if we need to look further.
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Monday, December 5th, 2022 AT 5:27 PM
