I own an 04 supercrew. I just bought a 240 amp Singer alternator, and there was a message in the box with my alternator. It says that because of the small pulley on the alternator that they use. I will need to shorten up my belt by 1/2"- 3/4". Will I need to buy a new serpentine belt, or can the belt tensioner be made to take up the extra slack? If I need a new belt, which vehicles belt has the correct length that I'll need to buy? Thanks

 

Don't belts show you their length on the packaging? If your tensioner can't take up the slack, just "guestimate" the different length you would need. I can't imagine this would be difficult, especially since you know it will be between 1/2 - 3/4" shorter. I'm sure you can find the OEM length spec online or at a dealership.

- Jack