Accessory Drive Belt Tensioner BAD...."squealing banshee". ?


HOOKED ON GT

GT Owner
Oct 26, 2006
468
Orlando & Australia
Ive still got some incessant squealing coming from the front of the engine.
I thought it was the water pump leak (all fixed) that had cooling system fluid spilt over belt and over some miles of driving it would just go away..... it didn't

Bought some "belt conditioner" and helped a bit (would stop squeal when warming up) but once driven a bit it would show up at 2.5-3k rpm and get a little worse higher you go.

Decided to run a test on the tensioner and had my daughter rev the car to 3k and with breaker bar add/subtract a little tension to belt tensioner.

What I found was the squeal got worse if I took a little tension off the tensioner wheel and better if I added a little.

Am I onto something here and potentially have a bad tensioner wheel/bearing?

I was planning on heading down to Boca next week but not sure I want a shit squeal sound when I want to get my hustle on

Stuart
 

B.M.F.

GT Owner
Mark II Lifetime
Jan 29, 2009
1,786
Minnesota
did you replace the belt? try that first
 

HighHP

GT Owner
Jun 3, 2019
439
Spokane, WA
Based on your test, sounds like belt slippage squeal. A couple of things can cause that. The belt V ribs wear out causing it to slip. Or, the belt tensioner is near it's end of adjustment range. Or, an old hard belt. Or, possibly a combination of all three. All are cured with a new belt as suggested by B.M.F.
 
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HOOKED ON GT

GT Owner
Oct 26, 2006
468
Orlando & Australia
The belt is in perfect condition (compared to Fords pics in the shop manual on what worn ones look like)
But saying that I thought I had the belts replaced 5+ years ago
I only found a work order for a oil pump belt that I supplied that was done 6 years ago.

I can get a driver side tensioner from the dealer anytime (4 in stock) but the accessory belt isn't disscontinued .

Thats a problem finding one?

Stu
 

twobjshelbys

GT Owner
Jul 26, 2010
6,064
Las Vegas, NV
Belts are like tires - they get old...
 

nota4re

GT Owner
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Feb 15, 2006
4,199
If you want to find the source of the squeak/squeal, you can use an ordinary spray bottle with water and selectively squirt it on a pulley. When you get the offending pulley, the squeal will stop for a few seconds or more.
 
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extrap

GT Owner
Mark II Lifetime
Jul 16, 2020
1,772
Gainesville FL
If you want to find the source of the squeak/squeal, you can use an ordinary spray bottle with water and selectively squirt it on a pulley. When you get the offending pulley, the squeal will stop for a few seconds or more.
So you think it's a pulley rather than the belt? Once the pulley has been identified, what's done to eliminate the squeak/squeal?
 

nota4re

GT Owner
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Feb 15, 2006
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So you think it's a pulley rather than the belt? Once the pulley has been identified, what's done to eliminate the squeak/squeal?
Yeah, I think it is a pulley. Find out which one - and replace. Belt squeal is typically unique, often louder, and subsides once enough heat builds up in the belt. I wouldn't completely eliminate the belt but from the comments in the thread, my bet is on a bad/failing pulley (or tensioner).
 

HOOKED ON GT

GT Owner
Oct 26, 2006
468
Orlando & Australia
Ok...
Went to dealer and got a new driver side tensioner...$69 odd bucks
Came home slackened the belt and spun by hand the guide wheel and it felt same as the band new one (slight resistance and zero sound...nice and smooth) hmmm
Start car and squeal starts, I carefully push the area the breaker bar locks ...and push it towards the engine and sound stops...hmm
I add some belt conditioner to rib side and squeal subsides I add a bit to flat side and maybe I notice some slip from belt? (engine tone changed a little) and then I see a wobble appear on the offending belt.

Lucky I turn car off and the section that was looking at stopped right at the bottom for me to see.
The outside rib had pealed off its seat
You can see that in pic when its rolled out..... dam
So now I need a newbie belt but no longer a ford supplied product.

BMF or nota4re... got this part?

Stuart
 

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extrap

GT Owner
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Jul 16, 2020
1,772
Gainesville FL
Great! And there are belts available, not OEM though I don't think. Rich Brooks got one for me.
 

HOOKED ON GT

GT Owner
Oct 26, 2006
468
Orlando & Australia
Great! And there are belts available, not OEM though I don't think. Rich Brooks got one for me.
Best to call him? .... or an email to find the belt?
 

extrap

GT Owner
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Jul 16, 2020
1,772
Gainesville FL
734-658-9498 He talks and texts, when he can.
 
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nota4re

GT Owner
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Feb 15, 2006
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Belts are readily available. Ford GT Belts
 
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HOOKED ON GT

GT Owner
Oct 26, 2006
468
Orlando & Australia
Belts are readily available. Ford GT Belts
Thanks a ton
You've smacked that one out of the park for me
Any preference on brand/model/size?
I don’t have a part number on me to check for compliance
 
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HighHP

GT Owner
Jun 3, 2019
439
Spokane, WA
This might help. You can see the part number trend. The 10 means 10 rib, 6 means 6 rib. The last four numbers are inches 0884 = 88.4.

4G7Z-8620-AABelt, Supercharger48.00
4G7Z-8620-AABelt, SuperchargerDayco 5100883, AC Delco Heavy Duty K100884HD
4G7Z-8620-AABelt, SuperchargerNAPA 25-100884, Gates K100884, Gates K100884HD
4G7Z-8620-BABelt, Main/Alternator29.00
4G7Z-8620-BABelt, Main/Alternator32.00Dayco 5060923, Continental 4060922
4G7Z-8620-BABelt, Main/Alternator32.00NAPA 25-060923, Gates K060923, Gates K060923HD
 
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B.M.F.

GT Owner
Mark II Lifetime
Jan 29, 2009
1,786
Minnesota
I buy new belts from oriellies..
 

HOOKED ON GT

GT Owner
Oct 26, 2006
468
Orlando & Australia
Thanks HighHP
I got an order in for a new belt for Friday arrival
Then the snake tracking begins to instal it
Looks hard
 
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PeteK

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Apr 18, 2014
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Kalama, Free part of WA State
If you don't already have one, get the shop manual too.
 
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HOOKED ON GT

GT Owner
Oct 26, 2006
468
Orlando & Australia
Got the belt a day early from Rock Auto and set onto getting it done as well as the new tensioner (old one seemed fine.

Had (decided to) make a custom T30 long bar to reach the top bolts for the oil belt cover + a couple other T30’s to help out

Got the old belt (took video of its positions before removal) and the new fella in and the oil belt back in and started up perfecto.
Belts tracking good.
 

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extrap

GT Owner
Mark II Lifetime
Jul 16, 2020
1,772
Gainesville FL
Got the belt a day early from Rock Auto and set onto getting it done as well as the new tensioner (old one seemed fine.

Had (decided to) make a custom T30 long bar to reach the top bolts for the oil belt cover + a couple other T30’s to help out

Got the old belt (took video of its positions before removal) and the new fella in and the oil belt back in and started up perfecto.
Belts tracking good.
Awesome! (y)