Screeching sound from drive belts at startup

[dumkid]

some new belts squeal for absolutely no reason and if you sprinkle some dusty dirt on it or drive down a dusty road the squeal will disappear. i think the new belts don't fit perfectly with the pulleys and the abrasive dust helps it get some grip until it wears to the pulleys. some people use talcum powder on squealing belts, but dirt is cheaper if you can find the right kind

 

[MaximaGuy]

I don't intent to spray, silicone or talcum powder or anything on a new belt. Its either a bearing on a pulley or a loose belt at this point.
Having said that this is my debug flow, tightening tension bolt, followed by chalk test, followed by belt removal and then taking it to my repair shop.

 

[tessaseveride]

I don't intent to spray, silicone or talcum powder or anything on a new belt. Its either a bearing on a pulley or a loose belt at this point.
Having said that this is my debug flow, tightening tension bolt, followed by chalk test, followed by belt removal and then taking it to my repair shop.

The silicone isn't a fix. It's a diagnostic step. A dab of silicone grease on the belt tells you immediately whether or not the belt is the issue. The belt isn't going to fly off during operation because you put a penny sized dollop of silicone grease on it.

 

[The Critic]

I don't intent to spray, silicone or talcum powder or anything on a new belt. Its either a bearing on a pulley or a loose belt at this point.
Having said that this is my debug flow, tightening tension bolt, followed by chalk test, followed by belt removal and then taking it to my repair shop.

If it wasn't squealing before the replacement, the noise is related to something you did. Retrace your steps, but most likely, belt is too loose.

 

[Trav]

The silicone isn't a fix. It's a diagnostic step. A dab of silicone grease on the belt tells you immediately whether or not the belt is the issue. The belt isn't going to fly off during operation because you put a penny sized dollop of silicone grease on it.

As a diagnostic step plain water will make it stop and not do anything negative to the belt or pulleys.

 

[SaberOne]

Just Tuesday, I threw the accessory belt after gunning the engine, and then letting off abruptly. Driving conditions required it but it effectively acted like a limp wrist type of deal, and there went the belt. I was on the most desolate road between Gila Bend, and Maricopa where the only thing out there is a train track and a few farms. I took the first dirt road I could find before the engine died. Cellular coverage was pretty much nonexistent so I was SOL. From a distance I could see this sign, and later it came to pass. Fortunately for me, a guy was turning down the same dirt road and informed me a shop was about 200m down the dirt road behind a bunch of corrugated metal and broke down tractors. Sure enough, the owner sent his worker down to my car and I was up and running in no time, they didn’t even charge me! Talk about the name on the sign being conveniently true!

 

[tessaseveride]

As a diagnostic step plain water will make it stop and not do anything negative to the belt or pulleys.

Why do you believe a dab of silicone will negatively impact the belt or pulleys? I've only ever had success diagnosing a belt driven noise with water on V belts, not serpentine belts, where as silicone works on both.

 

[Trav]

Silicone will cause more slippage under a load, it permeates rubber to some extent and puts a hard to remove film on pulleys. I have never had water not work on a serpentine belt.
Try silicone on a highly loaded V belt like a snow blower and see how well that works out, I use to use spray silicone on the chute to prevent snow buildup but some (very little) over spray got on the belts and rubber clutch disc. Not good.
There are some application that recommend washing a new belt with soap and water and drying before installation to remove any silicone release agents used in the machines. I don't usually do it but it is not bad practice if time allows.

It is common and normal to re-tension new belts after a short time with belts that are manually tensioned. I know of no belt manufacturer that recommends putting anything on belts. If you know of one that says to use silicone on the belts please post a link.

 

[tessaseveride]

Silicone will cause more slippage under a load, it permeates rubber to some extent and puts a hard to remove film on pulleys. I have never had water not work on a serpentine belt.
Try silicone on a highly loaded V belt like a snow blower and see how well that works out, I use to use spray silicone on the chute to prevent snow buildup but some (very little) over spray got on the belts and rubber clutch disc. Not good.
There are some application that recommend washing a new belt with soap and water and drying before installation to remove any silicone release agents used in the machines. I don't usually do it but it is not bad practice if time allows.

It is common and normal to re-tension new belts after a short time with belts that are manually tensioned. I know of no belt manufacturer that recommends putting anything on belts. If you know of one that says to use silicone on the belts please post a link.

A lot of aerosol silicone sprays contain propellants that damage rubber. Silicone grease will not affect rubber negatively. Think about all the brake slide pins that are lubed with silicone rubber grease from the factory. CRC manufactures belt conditioners. I'm not advocating fixing OP's vehicle with silicone. It's fine that water works for you in diagnostics. It doesn't for me, which is why I recommended silicone grease. OP still needs to find the actual source of the noise and fix it.

 

[MaximaGuy]

SaberOne: Definetly the mighty lord was looking down on your safety. This place looks like no-man’s land, glad you made it to see another day!!

 

[Nesterenko]

Just Tuesday, I threw the accessory belt after gunning the engine, and then letting off abruptly. Driving conditions required it but it effectively acted like a limp wrist type of deal, and there went the belt. I was on the most desolate road between Gila Bend, and Maricopa where the only thing out there is a train track and a few farms. I took the first dirt road I could find before the engine died. Cellular coverage was pretty much nonexistent so I was SOL. From a distance I could see this sign, and later it came to pass. Fortunately for me, a guy was turning down the same dirt road and informed me a shop was about 200m down the dirt road behind a bunch of corrugated metal and broke down tractors. Sure enough, the owner sent his worker down to my car and I was up and running in no time, they didn’t even charge me! Talk about the name on the sign being conveniently true!
View attachment 154394

I could tell you to go buy some lottery tickets but in this case you were so lucky that it's probably been all used up.

 

[dumkid]

those desert highways are more travelled than they look but you probably would be there for a few hours until someone came by. i always keep a few gallons of water with me

 

[MaximaGuy]

Are you sure the belt is tight enough?

Oh well. The belt was loose and it took many more turns to get the tension right.

All good and the belt noise is gone. Thank you Critic and others for your valuable suggestions.

 

[dogememe]

those desert highways are more travelled than they look but you probably would be there for a few hours until someone came by. i always keep a few gallons of water with me

Yep, a case of bottled water is always useful to throw in the trunk.