Odd noise from the new alternator

[Dadoo]

Just put in a new alternator in my 1986 C10 w/305 engine. At first start up, I had a high pitched squeal so I turned if off and rechecked the belt. I noticed the pulley on the alternator was hot to the touch. Thought maybe I didn't have it tight enough, so loosened the top bolt and pushed it a little more before tightening the bolt again. Now it's making a different noise. Hard to describe so I took a video.

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also, when the engine is off and I wiggle the belt, it makes this noise:

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Is the new alternator bad? Despite the website saying it was a direct fit, it came with a v-pulley instead of the 5 groove one I had, so I swapped the pulleys on the alternator.

I'll take any advice/tips on troubleshooting you've got.

 

[Ricko1966]

I'm concerned there is a spacer issue with the pulley swap. There is a spacer that goes between the front bearing and the pulley if it's missing or incompatible you will have a problem. Also overtightening belts to stop squeals wipes out alternator,water pump,power steering bearings. Always try to find the true cause. Weak battery,glazed belt etc.

 

[Dadoo]

I'm concerned there is a spacer issue with the pulley swap. There is a spacer that goes between the front bearing and the pulley if it's missing or incompatible you will have a problem. Also overtighten8ng belts to stop squeals wipes out alternator,water pump,power steering bearings. Always try to find the true cause. Weak battery,glazed belt etc.

Is there a specific tension that should be on the belt? and a way to measure it?

There was a spacer on the old one that I moved to the new one. Visually, the spacing all looked the same, but I know "it LOOKS the same" isn't the same as "it IS the same"

 

[Ricko1966]

Rule of thumb is 1/2 inch of belt deflection on the longest run of the belt. Take the belt back off make sure the alternator spins smoothly and freely.

 

[Edelbrock]

Just put in a new alternator in my 1986 C10 w/305 engine. At first start up, I had a high pitched squeal so I turned if off and rechecked the belt. I noticed the pulley on the alternator was hot to the touch. Thought maybe I didn't have it tight enough, so loosened the top bolt and pushed it a little more before tightening the bolt again. Now it's making a different noise. Hard to describe so I took a video.

xc_hide_links_from_guests_guests_error_hide_media

also, when the engine is off and I wiggle the belt, it makes this noise:

xc_hide_links_from_guests_guests_error_hide_media

Is the new alternator bad? Despite the website saying it was a direct fit, it came with a v-pulley instead of the 5 groove one I had, so I swapped the pulleys on the alternator.

I'll take any advice/tips on troubleshooting you've got.

How much did the alternator cost (with tax, delivery, etc).

Where did you get the alternator, what site?

 

[fast 99]

Bad rectifiers can cause noise. Check both AC and DC voltage.

 

[Dadoo]

Well - I'm a idiot! Long story short: I swapped spacers when swapped pulley's.

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Longer story (in case it helps other dummies like me): I loosened the new alternator to see if I could hear anything just spinning it by hand. That's when I noticed the fan blade was hitting the housing. Now, I could swear I spun it by hand before putting it in, but clearly I didn't or I would have noticed. So I took the pully off, compared the spacer to the one I had on the bench, and they were slightly different. Comparing the fan blades, also slightly different. So I had the wrong spacer paired to the wrong fan. Got everything put back together and it runs as expected.

Gold star to @Ricko1966! Thanks for the help!