Serpentine Belt Tension

M

Mike Z

TJ Enthusiast
Supporting Member
Lifetime Supporting Member
Joined
May 12, 2021
Messages
368
Location
USA
Hey there,
Replaced the serpentine belt on my 02 Wrangler, 4.0 with A/C last night. Took about 10 minutes and started the Jeep up and everything works fine. No noise from the belt. Installed a Gates Micro-V K060882 (6PK2243) 88 7/8 OC. This belt is referenced for the 02 Jeep.

My question: the tension on the belt does not seem all that tight. I know that Jerry and others have talked about the thumb test for deflection at the longest span of the belt. I'd say I can push the belt at least an inch. Since there is no real adjustment with the 02 tensioner, any ideas?

Has anyone else encountered this issue? Does anyone run a certain belt they like that has the right amount of tension?

Belt.jpg
 
Last edited:
with an automatic tensioner I don't worry about it unless it squeals.

With the earlier manual tensioners like I had on my 99, I use a ~$10 belt tensioner tool from NAPA. I found that using the typical rules of thumb I'm horribly inaccurate at checking belt tension by hand.
 
If the automatic belt tensioner can't get the belt tight enough my first guess is the wrong length belt was installed.
 
Ok, I figured it out, but I'm afraid to post what I found out for fear of getting my ass laughed off of this forum.

I was using the thumb test to check the deflection of the belt, meanwhile not realizing that when I was depressing the belt with force, the tensioner was moving ever so slightly. So, I held the tensioner tight and then did the thumb test with my other hand and the belt was appropriately tight.

Let it fly:ROFLMAO:
 
  • Love
Reactions: Jerry Bransford
There are marks on the tensioner that measure belt stretch and like @freedom_in_4low says, noise will tell you when there is a problem with the tensioner or the belt. I personally have never done anything else other than check for cracks and damage but I guess there's nothing wrong with giving the belt the finger.
 
  • Haha
Reactions: Kid Mechanic
You're right, pagrey. I looked for any wobble in the belt and listened for any noise and didn't see/hear any. The alternator was charging and every accessory was spinning. Should have just closed the hood. But, I do like the idea of giving the belt the finger ;)
 
  • Like
Reactions: pagrey
One thing to know about cracks in the belt indicating a problem. Cracks that go across the belt, from side to side, are normal and can happen shortly after installation. It's cracks that run length-wise that indicate it's close to failing.

Serpentine belt cracks.JPG
 
  • Like
Reactions: pagrey and DrDmoney
Jerry,
That's very helpful. I thought any cracking was a sign that a belt needed to be replaced. Appreciate the clarification.
 
Top Bottom
Back