Loud squealing noise
Thread Starter
Instructor
Joined: Dec 2012
Posts: 120
Likes: 1
From: Canton Georgia
Loud squealing noise
1986 corvette has a crate engine 350 vortec with all tpi parts (only about 3000 miles on engine). Everything is quiet when cold but after 10 minutes of driving I start to hear a squealing that gets loud like not wanting to drive loud. It can be heard from 600-1500 rpm but any higher it gets quiet. I ran the car without a belt and it made the same noise so it's not one of the accessories. Does it In park or neutral moving not moving. Oil pressure is great at 75 psi cold warm about 50-60 no over heating trans fluid looks full and red. It does have a new harmonic balancer on it not likely that it's squeaking but I guess possibly it can work it's way off belts line up good and it's not wobbling.
I really need to figure out what this could be its gets so loud! It's embarrassing to drive. I'd be more worried but the car feels good in all other regards no vibrations shifts good great power I'm just at a loss of what other possible thing it could be
I really need to figure out what this could be its gets so loud! It's embarrassing to drive. I'd be more worried but the car feels good in all other regards no vibrations shifts good great power I'm just at a loss of what other possible thing it could be
Race Director
Joined: Feb 2002
Posts: 11,618
Likes: 1,055
From: Compound in the Grove, Ga.
2026 Corvette of the Year Finalist - Unmodified
2025 C4 of the Year Winner - Unmodified
2024 C4 of the Year Finalist - Unmodified
2020 C3 of the Year Finalist - Unmodified
2019 C4 of Year Finalist (performance mods)
2018 C4 of Year Finalist
2015 C4 of the Year Finalist
St. Jude Donor '16
Put some bar soap on the belt see if it stops, remove belt and check all the accessory bearings and power strewing pump. Good luck
Le Mans Master
Joined: Jul 2004
Posts: 6,228
Likes: 698
From: Clifton Park, NY ............Clearwater, FL ... 85 Original Owner
Race Director
Joined: Feb 2002
Posts: 11,618
Likes: 1,055
From: Compound in the Grove, Ga.
2026 Corvette of the Year Finalist - Unmodified
2025 C4 of the Year Winner - Unmodified
2024 C4 of the Year Finalist - Unmodified
2020 C3 of the Year Finalist - Unmodified
2019 C4 of Year Finalist (performance mods)
2018 C4 of Year Finalist
2015 C4 of the Year Finalist
St. Jude Donor '16
Safety Car
Joined: Aug 2013
Posts: 4,430
Likes: 609
From: Minneapolis Mn
Kind of sounds like something I had with my T-Bird. It was a bear to track down but it turned out to be the aircleaner was the culprit. Changed out the filter and problem went away.
In your case, it's possible but could be other things. Being it happens when you're idling, I'd make up a pseudo stethoscope (just a piece of hose and a funnel) and when it happens, put the hose in your ear and start moving the funnel around the engine till it gets louder. Hopefully will get you into the area the sound is originating.
In your case, it's possible but could be other things. Being it happens when you're idling, I'd make up a pseudo stethoscope (just a piece of hose and a funnel) and when it happens, put the hose in your ear and start moving the funnel around the engine till it gets louder. Hopefully will get you into the area the sound is originating.
Thread Starter
Instructor
Joined: Dec 2012
Posts: 120
Likes: 1
From: Canton Georgia
It's just such an odd thing really it just causes a horrible noise. But I'm used to something like this making the car feel or run weird. I heard it could possibly be a loose bell housing bolt? It almost sounds like it could be underneath the car. Could a torque converter make a squeaking sound? The flex plate doesn't look cracked. This is gonna be a tough one
Racer
Joined: Oct 2014
Posts: 323
Likes: 21
From: Apache Junction AZ
You say the noise does not stop when you remove the belt. That eliminates almost everything in front except the harmonic balancer rubbing against something. The flex plate can be slightly out of alignment to rub a little. In my experience, I have not found other causes as you describe it. The bell housing can really make the sound reverberate a lot. So that would be suspect. The poster's advice above locating the noise is essential in tracking down the problem.
Melting Slicks
Joined: Dec 2009
Posts: 2,237
Likes: 287
It's just such an odd thing really it just causes a horrible noise. But I'm used to something like this making the car feel or run weird. I heard it could possibly be a loose bell housing bolt? It almost sounds like it could be underneath the car. Could a torque converter make a squeaking sound? The flex plate doesn't look cracked. This is gonna be a tough one
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Instructor
Joined: Dec 2012
Posts: 120
Likes: 1
From: Canton Georgia
Has anyone heard of excessive crank case vaccum being a problem? It seems if I crack the pvc valve a little the noise goes away! But once put back in it comes back. I need to find out why it is having problems breathing. Unless the extra vaccum just makes the rpm go up and the noise gets quiet.
Thread Starter
Instructor
Joined: Dec 2012
Posts: 120
Likes: 1
From: Canton Georgia
Well I had a little breather for a valve cover so I plugged the clean air hole on the throttle body and put the breather in. Something must have gone wrong car won't run. I guess it has a big vaccum leak from the valve cover. Pcv valve looked good on drivers side.
Thread Starter
Instructor
Joined: Dec 2012
Posts: 120
Likes: 1
From: Canton Georgia
Yeah it sounds like it can create a really deep vaccum and it looks for any air it can it sounds like a squeaking cause it's trying to get air from the rear main. Sounds like it's possible I'm gonna have to hook the hose back up tomorrow and see if I can fix it
Race Director
Joined: Oct 2008
Posts: 17,982
Likes: 1,074
From: Lansing MI
Sounds like metal to metal to me. Based on the general appearance of the engine compartment, I'm guessing there's somthing very very wrong somwhere. The good news is your probably not going to have to look for the problem for very long. I'm sure it's going to present itself in a very obvious fashion anytime now.