Heads up.....Napa list wrong size belt

[turbo nasty]

Napa has a size 40 belt when it should be a 35.
Even after the turbo engine choice. The belt will cause the tensioner to rattle.

 

[salvageV6]

The stock belt is a 640.

I use a NAPA 637 usually.

635's work great with a worn tensioner spring.

 

[turbo nasty]

With a 40 the tensioner is out of its window of operation. Worn spring would not have anything to do with that.
Take a peek and make sure you are tensioner mark is in the window if your running a 40, on mine the mark was past the window with the 40.
Funny thing is that advance shows a 35 and napa 40.

 

[pacecarta]

easier is to look at the tensioner wheel and where its sits in relation to the stud sticking out from the a/c compressor , if its at the center of the stud or has been rubbing on it the tensioner at its limit and belt is too long and youll get the ticking or knocking after blipping the accelerator

the 640 (64")belt is incorrect and some chains have corrected their computers , the 635 (63.5") is the one you want

and if you replaced the alternator and didn't swap the original pulley the replacement alternators have slightly smaller pulley which make the 640 way too long once they have a few miles on them

 

[scottyb]

640 is too long
637 will work for a while, but the tensioner will bounce on it's limit once the belt stretches
635 is the correct one.

I have tried both the 637 and 640 because various parts chains have them in the computer for our cars.

 

[turbo nasty]

Use the marks on the tensioner for its designed purpose and see if the belt is in the correct deflection window.
Good point on the pulley for alt replacement affetcingthe belt size.

More than anything this is a good info thread for future searches