Bad Squeal on throttle
 

Well, its more of a screech really. My 66 lemans with 70 455 has always had a bad squeal when stabbing the throttle. I finally got around to trying to diagnose it, I always thought it was the alternator but it's not.

I have 2 belts, alternator and power steering (no AC) and it screeches pretty bad when I hit the throttle to about 3k. If I pull the alternator belt it does it, if I pull the PS belt it does it. If I pull both it doesn't. Bought a new belt and still does it. Pulleys look pretty well aligned.

So I am assuming its the water pump bearing. But it seems really solid, no wiggle to it at all, no leaks. It's a PRW aluminum one. Could it be anything else causing this like the fan clutch? its a Hayden SD.

Any thoughts before I open it up to replace the water pump?

Thanks!

A lot of new belts these days do not have the proper wedge angle.
There metric from what I have heard.

I've got something similar and so far it is winning. My whine starts at about 3,200 RPM but doesn't get any worse with increased RPM. Same thing on the belts, squeal with both or either belt, but no squeal with belts removed. I replaced the water pump and it didn't make any difference. Then I replaced the 2797 severe duty fan clutch and that didn't help. Loud enough that I could use it as a speed control with the old gearing because it forced me to stay under 70 MPH. Very annoying when going through gears and I usually short shift to keep things quiet. At times I wonder if it isn't the fan and shroud combination creating the noise. Might pull the fan and fan clutch off but leave pulleys and belts on and see what happens.

Feel like I had something similar. I finally replaced my old factory WP pulley with a new aluminum unit from CVF and it fixed it.

If you are using 40+ year old pulleys I would replace those before I starting yanking my water pump.

First Guess: Both of you need to put the Severe Duty fan clutch in the recycle bin, and get a fan clutch actually recommended for your vehicles...which is almost certainly the standard-duty clutch. Guys install HD and SD fan clutches 'cause they "cool better", but they also lock up tighter, and don't release as fully, either.

The Severe-Duty clutch is so stiff it's almost like not having a clutch. Fan drag is more than the belt can transmit.

Second Guess: Get a Kricket I for V-belts, and adjust your belt tension AFTER using a straightedge to assure pulley alignment. Verifying pulley alignment is way more complex than most folks are willing to deal with, because you need to check from the drive pulley (crank pulley) to the top, and the bottom of the driven pulley, and then from the driven pulley back to the top and bottom of the drive pulley. It's a three-dimensional world, so the pulleys can be out-of-alignment in three dimensions. AND you have to account for the differences in pulley construction, some have a thicker front edge than others which means that you're really taking your measurements from the belt, not the front edge of the pulley.

Krickets are sold by multiple companies with various part numbers, and the plastic pieces may be yellow, or blue, or whatever. I got mine from NAPA when they cost less than half as much as they do now. Thanks, Biden. Get 'em wherever they're least-expensive.
KR1 for V-belts:
https://www.napaonline.com/en/p/NBHKR1

There's a Kricket II (KR2) for serpentine belts.
https://www.napaonline.com/en/p/NBHKR2

Third Guess: Look at your radiators/A/C condensers, make sure they can actually flow air through the fins. If they were totally blocked, the fan would stall and it probably wouldn't overload the belt(s); but if they're merely restricted they're going to cause increased drag on the fan, which overloads the belts.

My thoughts also.

belt squeal with SD fan clutch
 

fought thos as well with the SD clutch. hey its pulled air at idle awesome but did get
belt squeal at certain RPM. HD clutch worked well with no squeal. Also make sure PS
belt is wider to properly seat in pulleys. Also I choose the standard duty clutch as once
I installed a cold case radiator that really dropped temps. with standard clutch my highway
temps are perfect and better gas mileage. just have 10 degree temp creep at extended idle
when I am in traffic, drops to just above stat once rolling again.
using 7 blade AC fan from 76 TA with AC and AT.
Gerry

I have the same problem at 2800rpm. PS car. Replaced clutch fan with flex fan. Problem still there. Got correct width belts and new drive and ps pulleys. Double pulley for water pump was not available. Still there. Had to replace ps pump. Still there. Water pump is a flow kooler with 2k miles on it. Car is down right now for some upgrades. Thinking about getting a set of billet aluminum pulleys.

I had the squeal problem and after trying 3 sets of new belts I bought a reproduction belt, first guess was PS, and haven’t had a problem since. I agree with Steve that the new belts could be an issue, often overlooked.


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OP said it still does it with all belts removed... its not belts.

He posted that with any of the two belts on it did it, but with both belts off it did not.

At first I also thought he said that it did it with both belts off and a thought to myself the last time I had a screech sound that was not the belts it turned out to be a cracked flexplate in the end.

You need a correct 17mm belt for your power steering instead of a smaller 15mm like the alternator uses. Parts stores almost always get it wrong.https://forums.maxperformanceinc.com...+steering+belt

Oops, early morning post misread the comment.

if it doesnt do it with both belts removed, that definitely could be belt related. I recently bought a 80 TA & had to drive it home 9 hours, test drive around city streets was fine, but once I hit the interstate at ~2800 rpms I noticed a bad screech sound that would stop below ~2800 then start again under light load getting to that 2800rpm. Stopped for gas & checked the belts & even tightened them, didnt change the noise. Made it home and did more checking, finally decided to pull the clutch fan to clean & repaint, started it up with out the fan & the noise was gone. Turned out it was a bad clutch that only made noise at that certain rpm & above.

If its not belts, check the clutch of the fan & try pulling it to see if the noise stops. Can run the engine with no fan or belts for a short time to check for noise.

I bought the aluminum pulleys from Ram Air Resto. Took about a year to receive them at the time, but they work great on my 66 with PS, AC, high flow WP, and HD fan clutch. Gates belts, no squeal under any conditions. They're quite costly, but they work great and look nice.https://uploads.tapatalk-cdn.com/202...0a5dde9f21.jpg

I think the "V" in the pulley gets "polished" and slips, no matter how tight the belt is. I would pull them off and bead blast the V to roughen them up somewhat.

I need to bookmark this page...having similar issues.

The bead blade suggested is a great idea to try out, but if your going to a auto machine shop to get that done then see if they have a shot peen cabinet.

2 minutes in there and there will be texture for sure in the grove.

Just want to take moment to apologize for the awkward formatting of my post above. For some reason, when I add a photo as an attachment to a post using my smartphone, that's what happens. Looks normal on the phone, but is all kinds of screwy when viewing via PC. I'd edit it to fix, but can't do that anymore.

Are the "reproduction" belts the same as off the shelf auto-store? Or do they have a different width or angle?

Let's not be talking bad about my beloved SD fan clutch! ...but seriously, I have them on all my Pontiacs and have talked another six or seven people in our GTO club into installing them. So round that up to about a dozen and only my car has developed a squeal. Our two '65 big cars have one belt to run the water pump and alternator and 19.5" fan with the SD clutch and that one belt doesn't squeal on either car.

The really weird thing is hot or cold, battery low or fully charged, that damn squeal is exactly at 3,250 RPM and 100% repeatable. You would think that different conditions at different times would make the squeal at a higher or lower RPM but it is always at exactly the same Engine speed - and racing the engine in the driveway or buzzing down the freeway.