Serpentine Belt - SIZE CHANGES!

AdamIsAdam · **Posted:** Thu Jun 01, 2006 10:02 pm

My serp belt ripped when my tensioner pulley seized when I was about 140 miles from home last week.
(for pics of the shredded parts, look at the last few pics in this group:
http://www.photoworks.com/share/shareLa ... r_25pr_ps2 )

On the road, I was able to get an replacement aftermarket pulley and belt. It got me home fine. the next day, the belt flew off 2 miles from home and I made it to my garage. There I found the idler pulley's bearing were shot, so I replaced that pulley and got a new belt just to be safe.

A week later, and I smelled a burning scent again. I stopped in to a Jeep dealership and opened a HUGE can of worms.

Very VERY long story made slightly shorter:
There are tech releases on the belts. They changed the belt sizes THREE times. Plus, they now use smaller pulleys too.

So I bought a whole new tensioner assembly complete with new pulleys but had to go to two dealerships to get the right belt. With the new belt and tensioner assembly in place, the spring is loaded back 1" whereas before it was only under .5" of tension. I feel better about this now.

So if you get the new assembly, you need the newest, shortest belt. There are several PN's and a few are close, but the smallest one, and the last tech release says to use PN 53013905AA.

this PN is so new, that two aftermarket stores did NOT have the cross reference yet! Be carefull!

KJed · **Posted:** Wed Jul 12, 2006 1:54 pm

My tensioner went so I had a new one but on. The tensioner started to make noise they have replaced it twice and it is still making the noise. This may be the problem. Thank you for posting.

AdamIsAdam · **Posted:** Wed Jul 12, 2006 2:01 pm

what kind of noises and how do you know it's coming from the tensioner?

KJed · **Posted:** Wed Jul 12, 2006 2:11 pm

It sounds like a clicking noise. It only does it when you step on the gas for a few seconds. It is more noticable when the A/C is on. If you look under the hood you can see the tesioner jumping and hear it clicking. I work for the dealer they have been stumped.

AdamIsAdam · **Posted:** Wed Jul 12, 2006 2:24 pm

Interesting.

Well, they did redesign the part (hence the newer, smaller belt). Maybe you got an old one or a bad one. Should be easy enough to swap out and try it again.

I wonder... is it possible that another accessory (like the AC) is not spinning freely and smoothly, so that when it comes on it binds slightly, causing the tensioner to load or compress somewhat?

When my belt was off, I spun everything to make sure that all pulleys rotated freely and smoothly. But that won't help with the AC compressor when it's on and under load. I don't know how to check that. Hmm. Can you get a belt for a NON-AC model and by-pass the AC to see if the problem goes away?

(I'm good, ain't i? Just call me click, clack and clock. I'm clock, the missing tappet brother.)

KJed · **Posted:** Fri Jul 14, 2006 7:12 pm

They did check all the pullies when they replaced the second tensioner they put on.
I mentioned what you said and they are looking into it.

jpzkj · **Posted:** Fri Jul 14, 2006 10:18 pm

Just got our '04 back from the dealer ( idler pully replacement ).

The "napa" belt that I bought in '04 and have had under the seat was put on by the dealer and made some noise. The swapped it for the new 'mopar" belt and no noise....

That seems to confirm the belt /pulley changes doesn't it.

AdamIsAdam · **Posted:** Sat Jul 15, 2006 7:03 am

Did they replace just your idler pulley (about $25) or the whole tensioner assembly ($95)? And was it the idler pulley (smooth one) or the tensioner PULLEY (ribbed one)?

The new, smooth IDLER pulley is smaller than the old, and it comes with the new tensioner assembly. So yes, you need the new smaller belt with that pulley. The difference is small, about 1/2", but that's enough to keep the spring loaded to the right amount.

KJed · **Posted:** Sat Jul 15, 2006 9:27 am

They replaced the whole tensioner assembly.

Joe Jeeper · **Posted:** Fri Jul 28, 2006 9:40 pm

Had new tensioner put on about a year and 1/2 ago after ratcheting sound. Thought it was from wheelin' and the mud and all. Put a aftermarket belt on about 6 mths later. That belt started screaming 2 mths ago it had been on 11mths so I went and got a Mopar belt, the dealership said they probably put a new belt on with the tensioner, checked the repair order , Oh contrare no belt listed. They were pretty confused on what tensioner I had what belt I had showed them the old mopar belt and they matched it to #05135745AA. Now no whinning but the tensioner is ratcheting again especially with A/C on. Does anyone know how to match tensioner to belt or vice/versa cause the dealer doesn't seem to have a clue! Joe

AdamIsAdam · **Posted:** Fri Jul 28, 2006 10:06 pm

Yes! I did a write up on this after going to 3 aftermarket parts stores and two dealerships! If you have a new tensioner assembly, then you need the newer and smaller belt. That could be your problem. There were at least 3 "superceeded" part numbers. If your idler pulley (not tensioner pulley, but the idler one) is plastic now and not metal, you have the smaller one.

Search for my thread on this. I did it in May after I went through 4 belts in 3 days, etc.

I think mine went after spending the weekend at the Jamboree in sandy water up to my headlights.

AdamIsAdam · **Posted:** Fri Jul 28, 2006 10:07 pm

I have the part number on that thread, but also in my Jeep if you need me to go into the garage to get it.

cowpie · **Joined:** Mon Jul 25, 2005 9:00 am **Posts:** 26

I had the rattling noise when idling in drive or reverse. The belt that was on the napa computer was the OEM size listing for the 3.7L. The newer belt is a bit shorter. I do know the part numbers of the gatorback belts that do and do not work. The parts stores will spec a 87.5 inch belt gatorback part # 4060875. That is the one that is too long if your tensioner is bottoming out and rattling. I cured the problem with a 87.2 inch belt. Goodyear Gatorback part number 4060872.

I sure do like having a vehicle that has enough room under the hood to change the belt in the autoparts store parking lot without tools! Just a strong arm and a leather glove.

TnRebel · **Posted:** Sat Aug 12, 2006 11:51 am

well guys it hasnt been fixed yet -- I just got my 06 with 7333 miles back from the shop to replace the tensioner and belt

AdamIsAdam · **Posted:** Sat Aug 12, 2006 12:08 pm

TnRebel wrote:

well guys it hasnt been fixed yet -- I just got my 06 with 7333 miles back from the shop to replace the tensioner and belt

What happened? Did the belt break? Tensioner fail? etc?

TnRebel · **Posted:** Sat Aug 12, 2006 8:54 pm

The tech said the the spring broke in the tensioner housing and the belt got in the the fan pully before I could get it to the shop

bootsers · **Posted:** Wed Sep 27, 2006 12:10 am

Thanks a bunch for the info. The spring on the pulley broke last night. Jeff Macgyvered it with my umbrella spoke to get it home. While the libby was at the dealer I did a search and read your post and saved my self a bunch of trouble. The dealer didn't have a clue about the different belt. Thanks again and keep all this good info coming.

Joe Jeeper · **Posted:** Sun Oct 29, 2006 4:39 pm

I'm on my third belt tensioner, a new belt, new a/c compressor (not sure why, dealer said it made noise?) and I still have the racheting noise under the hood from the tensioner. My dealer said they know about the belt and tensioner match but I still have the noise. I haven't had a break-down due to it, knock on wood, but don't like it! Any suggestions? Thanks, Joe

bootsers · **Posted:** Sun Oct 29, 2006 9:08 pm

Joe,
After an intial noise free period, I am in the same boat as you. My dealer was to place a call to engineering this week. If I find out anything, I will let you know.

tjkj2002 · **Posted:** Mon Oct 30, 2006 1:17 pm

Quote:

Joe Jeeper
Belt Tensioner.
I'm on my third belt tensioner, a new belt, new a/c compressor (not sure why, dealer said it made noise?) and I still have the racheting noise under the hood from the tensioner. My dealer said they know about the belt and tensioner match but I still have the noise. I haven't had a break-down due to it, knock on wood, but don't like it! Any suggestions? Thanks, Joe

Quote:

bootsers

Joe,
After an intial noise free period, I am in the same boat as you. My dealer was to place a call to engineering this week. If I find out anything, I will let you know.

I had the same problem you guys are having,the factory tensioners are crap(3 gone in 20,000 miles).I ended up going to Advance Auto Parts and got a Daystar replacment tensioner for $55 and have ran it for 26,000 miles with no troubles.Might want to check them out.

Serpentine Belt - SIZE CHANGES!

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