Incessant belt squeal at idle
- Thread starter Ihatetochangeoil
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The drive pulley on our 2001 Impala with the 3.4 L engine is a combination drive pulley and harmonic balancer all in one unit. It is made with an inner pulley that mounts to the drive shaft and an outer pulley, and a black rubber between the two pulleys. Over time and use the rubber between the two pulleys allows the outer pulley to migrate (move) so it is no longer perfectly aligned with the inner pulley. When it gets really bad the belt will fall off. Ours failed with a little more than 80,000 miles on it a couple of years ago. You have to remove the right front tire and inner wheel-well to access the pulley to replace it.
The OP vehicle is probably the same design.
Check your drive pulley / harmonic balancer to see if the outer pulley is not perfectly aligned. if the outer pulley has moved replace the entire two pulley and rubber assembly before it gets so bad that it causes the belt to fall off and leaves the car with no power steering and no water pump and no alternator.
The OP vehicle is probably the same design.
Check your drive pulley / harmonic balancer to see if the outer pulley is not perfectly aligned. if the outer pulley has moved replace the entire two pulley and rubber assembly before it gets so bad that it causes the belt to fall off and leaves the car with no power steering and no water pump and no alternator.
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Have you done a load test on the alternator? If the pitch changes, the alternator could be at fault, Ive seen where they are hard to turn under load and the belt starts screaming. Ive also heard the alternator bearing screaming like a belt too. Worst case, toilet bowl wax works great IMO.
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Thanks guys. Y'all made me think. There is no idler pulley; it's built onto the OEM Belt tensioner, which I replaced with OEM (and kept the old one), probably nothing wrong with it. The power steering is smooth as butter and has never been serviced other than fluid changes, there are no missing washers or misalignment. With the vehicle garaged, there is really no rust to speak of on the pulleys. I could feel no resistance or "wobble" on any pulley with the belt off. I put talc powder on the belt ($1.99) because it was easy and cheap, no change.
More than one poster mentioned Harmonic balancer....I finally drove the car until the howling started....Shut the engine down & restarted, howling came back immediately....Shut down again & removed the belt, then restarted; howling still there with nothing turning except the Harmonic balancer.
Ordered a new AC Delco one from RockAuto. Don't know why I never thought of that before, but it has to be an easy, sure fire way to troubleshoot this noise. Obviously can't run the engine very long without the water pump or alternator turning, but all it took was literally seconds.
I sincerely appreciate all who contributed and helped me brainstorm. Love this forum. Solution so simple....Thanks again kschachn, WishIhadatruck, Snagglefoot, krismoriah72, Wolf359, clinebarger, and those I haven't named specifically.
More than one poster mentioned Harmonic balancer....I finally drove the car until the howling started....Shut the engine down & restarted, howling came back immediately....Shut down again & removed the belt, then restarted; howling still there with nothing turning except the Harmonic balancer.
I sincerely appreciate all who contributed and helped me brainstorm. Love this forum. Solution so simple....Thanks again kschachn, WishIhadatruck, Snagglefoot, krismoriah72, Wolf359, clinebarger, and those I haven't named specifically.
Easy test: while the belt is squealing at idle, spray or pour water on it. If it gets quiet, you have an alignment or bearing issue. If it gets noisier, you have a tension and/or friction issue.
I fought this on my '07 4Runner last Summer and it was a bear. Mine was a bearing issue, the idler pulley on my tensioner had a bearing failure that only showed symptoms when hot. I pulled the belt repeatedly, all pulleys felt fine on rotation and wobble check. With a squeal at hot idle, water on the belt would silence the squeal.
Mechanic's stethoscope finally found the source (these are a great investment of $20) when I probed the tensioner pulley bolt, it was grinding like a rock crusher.
I fought this on my '07 4Runner last Summer and it was a bear. Mine was a bearing issue, the idler pulley on my tensioner had a bearing failure that only showed symptoms when hot. I pulled the belt repeatedly, all pulleys felt fine on rotation and wobble check. With a squeal at hot idle, water on the belt would silence the squeal.
Mechanic's stethoscope finally found the source (these are a great investment of $20) when I probed the tensioner pulley bolt, it was grinding like a rock crusher.
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