1974 corvette squealing engine noise
Thread Starter
Instructor
Joined: Jan 2017
Posts: 175
Likes: 14
1974 corvette squealing engine noise
I drove my Corvette yesterday and when I accelerated, I heard a squealing noise coming from the engine (It sounds like closing a door that hasn't been oiled in a while). This only happens when I Accelerate, as soon as I let off the gas or keep the pedal steady, it stops.
I already checked the engine belts and all pulleys (water pump & Crankshaft included) and all were tight. What else should I check? could it be the electronic choke or the accelerator control cable attached to the carb making the noise? if so would it be safe to use WD-40 or some other lube to quiet the noise?
I already checked the engine belts and all pulleys (water pump & Crankshaft included) and all were tight. What else should I check? could it be the electronic choke or the accelerator control cable attached to the carb making the noise? if so would it be safe to use WD-40 or some other lube to quiet the noise?
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
I am 99% sure its a belt. Some of these C3 have three, four or five fan belts. One of them is going to squeal.
I had the same issue with belts that were really not that old. But the newer belts don't seem to ride in the pulley groove like before.
I know its a PITA but you could tag the position and direction of rotation of each belt with masking tape & felt pen. Then starting in the front of course, remove them all. Flip them all so they are spinning in the opposite direction. Doing that will remove that squeal. Belts get a glaze-over on the sides of the rubber but still have useful mileage left.
Using any type of lube or dressing on a belt will quiet it down but does nothing to help the source of the squeal, which is slipping.
I had the same issue with belts that were really not that old. But the newer belts don't seem to ride in the pulley groove like before.
I know its a PITA but you could tag the position and direction of rotation of each belt with masking tape & felt pen. Then starting in the front of course, remove them all. Flip them all so they are spinning in the opposite direction. Doing that will remove that squeal. Belts get a glaze-over on the sides of the rubber but still have useful mileage left.
Using any type of lube or dressing on a belt will quiet it down but does nothing to help the source of the squeal, which is slipping.
Last edited by HeadsU.P.; Jan 11, 2019 at 08:41 AM.
Race Director
Joined: Mar 2016
Posts: 14,406
Likes: 8,212
From: Napa Valley California
Belts will also take a set when the engine is not started for a period of time.
As the belts age, the rubber hardens and in the cold they will squeal when you rev the engine.
As stated earlier they are slipping even if they appear tight.
The best thing to do is replace the belt.
As the belts age, the rubber hardens and in the cold they will squeal when you rev the engine.
As stated earlier they are slipping even if they appear tight.
The best thing to do is replace the belt.
Le Mans Master
Joined: Jan 2001
Posts: 6,743
Likes: 1,385
1. Get some belt dressing spray at your local auto parts store. Spray one belt at a time and go for a drive. It will last long enough for you to check on a drive. Do one belt at a time so you can narrow it down.
2. Buy a BRAND NAME belt. I wasn't believing this until a guy at NAPA told me that when I could not get my belts to quick screeching. Sure enough - got a brand name belt and haven't had squealing since.
Last edited by carriljc; Jan 10, 2019 at 09:12 PM.
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I had the same issue on my '75. It was the alternator belt. I thought it was plenty tight. But I put a pry bar on it and made sure the belt was super tight. Squeal was gone.