New Alternator. Belt Over Tensioned. '04 Explorer

[KaitoTakeshi]

I just recently put a new Mechman alternator on my Explorer.

The new alternator has a pulley with a diameter of 1.75"
The original alternator has a pulley with a diameter of 2" - 2.2" (taken from different sources)

Now the tensioner seems to be putting too much tension on the belt. Causing a terrible squeal. The tensioner looks like it is out of where the marks are for correct tension.

I have tried using the original belt and a brand new one, they both cause the squeal.

• How can I fix this problem?
• Can the tensioner put too much tension on the belt?
• If the belt is too long can that cause the tensioner to apply too much pressure?

2004 Ford Explorer XLT V6 4.0

(2002 Ford Explorer Motor)​

 

[swshawaii]

Longer belt reduces tension, shorter increases. Close to center line between the wear marks ideal.
Left mark is looser, right tighter. Also make sure routing is correct using the hood decal or manual.

Stock length replacement Gates belt is 85 7/8" (K060854)
http://www.rockauto.com/catalog/x,carcode,1427767,parttype,8900

See page 3 for shorter lengths. K060849-845-840, etc.
http://www.gates.com/oreilly/PDFs/SizeListings.pdf

 

[KaitoTakeshi]

Thank you for the reply! My wear indicator is actually about a quarter of an inch to the left of the indicator. But the belt only seems to have at the most 3/8" of slack. The picture you show here is exactly what mine was at before the alternator replacement. I will take a picture in the morning to show wear my indicator is.

 

[KaitoTakeshi]

Got the tension set up correctly! The belt I used was about 3/8" shorter than stock.