Chasing a squeal, need opinions.

[BLACKLS5]

I've been chasing a squeal in my Dad's '71 4-speed Chevelle and am looking for opinions on what it may be. I sure sounds like it's coming from the front of the engine but I know how noises can travel. Here's what I've done to this point... Eliminated the power steering by taking the belt off, tried two different alternators, changed all the pulleys, took the fan clutch off and replaced it with a spacer, numerous different belts. I thought it had to be the water pump right? It's the last thing on the front of the engine, Nope. It starts about 3500 rpms and it sounds like a dry bearing.

Early in my testing I checked to see if it did it with the clutch in or out. It makes the noise regardless. Neutral or in gear same thing. I thought that would eliminate the throw out bearing but maybe not? I'm getting a bit frustrated as I must be overlooking something simple, I just don't know what. Anybody have any suggestions?

Thanks, Troy

[SuperNovaSS]

Have you run it without any belts?

Jason

[BLACKLS5]

Originally Posted by SuperNovaSS

Have you run it without any belts?

Jason

I did, but didn't take it down the road. I just revved it up in the driveway. I didn't hear the noise so I assumed it was something that the belts drove, Alternator, water pump, power steering pump or fan clutch. I've tried different belts and have a Gates brand on there now.

[big gear head]

I put a new water pump on my Mustang a few months ago. It just started squealing last week. Looks like I'll be replacing it again.

[PeteLeathersac]

'

Does sound stop when engine warmed up or continue squealing?
Do all driven part seem Ok when pulleys hand spun w/ belts off?
Are all belts exactly correct for application, not just length but width/bevel shape?
With everything assembled, do any brackets appear slightly bent/missing spacers causing pulley misalignment?
If able to create sounds w/ vehicle stationary and helper behind the wheel, try listening through a 6' piece of garden hose moving hose tip around to suspect areas.
The water pump is a good thought also if sounds are from clutch area, when was clutch last changed also don't forget pilot if you crack things open.
Best of luck and keep us posted of what you find.

~ Pete

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[JoeC]

maybe the fuel pump ?

can try to cut open the oil filter to see if there is any metal

also vacuum leak or a carb problem can make a weird noise sometimes

[SuperNovaSS]

It sounds like it is something driven by the belts and is not the power steering. Why do you say its not the waterpump?


Jason

[RALLY]

Does the squeal start when the engine is under a load? Or just bringing the engine up to 3500 RPMs when its in neutral? Is the distributor making this noise? Agree with Pete, use the short hose or pipe and listen to all areas of the engine.

[BLACKLS5]

It does it with the car in neutral and under load. It has GM deep groove pulleys on it now but I switched back to the standard pulleys to eliminate the pulleys as a problem. Although it will spit the fan pulley off at high RPMs with the standard groove pulleys. The alignment sure looks good to me. Is there a sure fire way to check other than eyeballing it? Width and bevel of the belts? I don't know, I've tried NAPA, and O'reillys belts. Tell them what the application is and go with it. Gates brand on there now. Jason, I say no on the water pump because that was the last thing I changed a couple of days ago. I thought I had it narrowed down to the pump. It was the last rotating part on the front of the engine.

Let me throw this out there... I swapped out his 396 a couple years ago with the current 454. With the 396 it had a squeal when you shifted, just when you shifted, so I figured it was a bad throw out bearing. Obviously installed a new bearing when I changed motors and noise was gone. It was fine for a couple of summers. Last summer he mentioned that it started to squeal above 3500-4000 rpms. Would a worn bearing retainer that the throw out bearing rides on cause something like this?

Thanks for the suggestions. I'll try the hose idea or buy a cheap stethoscope to try and isolate the noise a little better.

[napa68]

To eliminate the TOB discussion, just back off the preload on the clutch fork and pull it away from the pressure plate.

Not knowing what is in there for a TOB, I'll offer this. Many of the TOB's provided in clutch kits are not a very good quality piece. Many are plastic. There happens to be one in my 71 Trans Am and it makes noise (albeit I can change it by playing with the clutch pedal).

I will be changing the TOB in my TA (and any other clutch job I do) with this.....
https://www.amazon.com/BCA-National-.../dp/B000YPKU2O.

By what you have shared, I don't know if that is indeed your problem. Is there a forum member that is close to you? Speaking for myself, when I get frustrated I get my head spinning. Sometimes a fresh mind, ears, and set of eyes is the best way to solve a problem.

Tim