Screeching Sound

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Got2Gnow

Got2Gnow

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I have a 1971 Dart Swinger with a 318. It makes a terrible screeching sound with the engine running. The noise increases as rpms increase. Sometimes the noise lessens as the car "warms up", but seems to be getting worse as time goes by (it's been doing this for about 3 years (~800 miles a year (summer cruiser))).

I've wiggled the water pump to see if there is any "play" in it. It feels OK.

Could the screeching sound be from the alternator? Maybe bad bearings? Any way to lubricate the bearings?

Any other ideas?
 
Could be an alternator bearing,, how about a loose fan belt..?? Splash/squirt a little water on the fan belt when it's running and noisy,, if the noise goes away for a bit,, the belt needs tightening..

Could be alotta things..

Can you post a video,,??
 
Well, you could try bar soap on the belts as a lubricant and see if the noise goes away. If it doesn't then try a long screwdricer or stethiscope on all the driven accessories and see if you can pick out which one is making the noise.
Also you could take off the belts and try spinning each accessory and check for roughness in the bearings and excessive play.
 
Alternator bearings make noises that change as they warm up. They cant be lubricated. The alternator will fail to charge or lock up and cook the belt eventually.
Set the belt off it and spin it by hand. If it doesn't spin freely, there's your sign.
 
You might just need new belts. If they have been screeching for years and the belts were loose, by now they are probably trashed.
 
Hey guys I applied bar soap to the belts and it cured the screeching!
Is there a more permanent solution? A belt dressing?
 
Last time I heard a screeching sound when working on my car, it went away when my ex-wife left the garage..... LOL!
 
Belt alignment! Sometimes a washer, or two may be needed to make sure the belts run true. I did all the soap, tightening, loosening. Then one day my neighbor (an old timer who knew his way around an engine) eye balled my alternator belt, and sure enough it was just a bit behind the crank pulley. Added a 3/32 washer, and bingo, the squeal at 45 mph went away. So eye ball the alignment real good.
 
Got2Gnow said:
Hey guys I applied bar soap to the belts and it cured the screeching!
Is there a more permanent solution? A belt dressing?
Click to expand...

Alignment of the pully's is number one thing to chk.
One thing to keep in mind also is that a worn belt gets narrow and can drop down in the groove too far and cause squeeling.
The dead giveaway is the belt being below the edges of the pully it's running on, and feathered edges on the belt top surface.

Belt dressings often make it worse.
 
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