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440 6 Pack squealing noise only when completely warmed up

8formulas

8formulas

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440 six pack 4 speed.

I hate having to bother everyone with this but I can't figure out where this squealing noise is coming from. It sounds exactly like a bad belt. So I did the obvious and removed both belts (alt and PS). Start engine and the squeal is still there. I used a long screwdriver and tried to listen to the timing cover, distributor, PCV valve, block, heads, valve covers. I hear nothing at the screwdriver handle. It sounds like it's coming from up top and closer to the front carb area. Could it be a vacuum leak?

More info: it does NOT make a sound when the engine is cold. It only happens when the engine temp reaches about 150 degrees. Also, if I rev the engine, the squeal gets louder. You would swear it was a bad belt but it's not because I removed them.

Thank you in advance for any tips. Hoping someone else experienced this. Very frustrating.

Mike
 
You said no belts so it can't be water pump bearing. Did you work on anything and the squeal started? Spray a little carb cleaner base of carbs.
 
If you have a vacuum leak, spraying something flammable at it will make the engine rpm increase right away. May even change the sound of the leak.....if that's what you have.
 
Thank you everyone. It's too hot today here in CT to be messing with it. Tomorrow I will try the carb cleaner trick. If I find something, I will be sure to let you know.
 
8formulas said:
Thank you everyone. It's too hot today here in CT to be messing with it. Tomorrow I will try the carb cleaner trick. If I find something, I will be sure to let you know.
Click to expand...
If you have a nicely painted engine and don't want to be spraying carb cleaner, a small propane torch, unlit of course, will get the same results.
 
How is the oil pressure as the engine warms up? It sounds like a spun bearing, squealing as the oil pressure drops. Just a guess without hearing it.
 
RemCharger, Yes, I have a breather.

cosgig, oil pressure is about 55lbs as the engine warms up and it will drop to 45lbs when fully warmed up. Oil pressure never goes below 40lbs.
 
How about a squealing bypass valve inside the oil filter? Change the filter and see what happens. That's all I got...except...

I suppose an oil pump pressure relief valve could squeal (broken/weak spring), but I don't know if you would see pressure pulsations on a gauge tee-d in at the sensor unit.
 
I usually have a suggestion, but this has stumped me. A dry cyl? Try removing one spark plug at a time.
 
I think RemCharger nailed it. I removed the breather (temporarily of course), drove the car and got it up to operating temperature. Squealing is gone. I believe the breather was plugged up and not allowing fresh air to enter the crankcase. I sprayed carb cleaner into the breather and swished it around. Let it soak for a bit and dumped it out. Lots of tiny particles came out. Repeated the process 2 more times. More particles came out.

I literally just discovered this a half hour ago. Squealing is gone but if the squealing noise returns, I will reply back to this thread. Thank you to everyone who tried to help me. Honestly, the breather was the last thing that I thought would create a belt squealing sound.

Thank you,
Mike
 
8formulas said:
I think RemCharger nailed it. I removed the breather (temporarily of course), drove the car and got it up to operating temperature. Squealing is gone. I believe the breather was plugged up and not allowing fresh air to enter the crankcase. I sprayed carb cleaner into the breather and swished it around. Let it soak for a bit and dumped it out. Lots of tiny particles came out. Repeated the process 2 more times. More particles came out.

I literally just discovered this a half hour ago. Squealing is gone but if the squealing noise returns, I will reply back to this thread. Thank you to everyone who tried to help me. Honestly, the breather was the last thing that I thought would create a belt squealing sound.

Thank you,
Mike
Click to expand...
Good news. If the breather is truly plugged, the squealing was likely from air being sucked in the crank seal.
 
If the breathers had that much debris in them. I would buy new breathers and replace them. That may even be some debris from them deteriorating internally. You don't want that going in your engine.
 
6PKRTSE said:
If the breathers had that much debris in them. I would buy new breathers and replace them. That may even be some debris from them deteriorating internally. You don't want that going in your engine.
Click to expand...
Yeah, you're right. I will replace it. Thank you.
 
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