Replace Belt Tensioner?

[profdlp]

I plan to replace my serpentine belt very soon. My 2007 Liberty is just over the 61,000 mile mark. Is there any reason I should (or should not) replace the tensioner as well?

I am doing this because for some time now my battery voltage has been reading lower than usual. I bought a new battery last February, so I doubt it is that. My battery problems started about the time I replaced my water pump (also last February) and I am wondering if the serpentine belt might have gotten stretched out during the process. I understand that it could also be the alternator, but figured replacing the belt and keeping the old one as a spare would not be a bad idea at this point.

 

[uss2defiant]

are the pulleys still good?

 

[CzarKJ]

I replaced mine at 120k. Was still good but I was doing the belt (which was still good except for being well used and is now a spare) and thought the same thing.

 

[tommudd]

In 218000 i have replaced mine 4 times, too me its cheap insurance to not have it fail on a trip

 

[profdlp]

What's the difference between these:

SERPENTINE TENSIONER

and:

SERPENTINE IDLER PULLEY

Is the first the one the whole assembly and the second one the pulley only?

 

[M38 Bob]

There's quite often one of each. The Idler is mounted solid, and just keeps the belt from touching something non-moving. The tensioner is spring loaded and does just what it says it does.

Bob

 

[uss2defiant]

must be. crazy how close in prices they are.

 

[profdlp]

I think I'm going to order just the tensioner and the belt. If the pulley looks funky when I change them out I'll stuff it in there later. I'm mainly interested in eliminated a stretched belt and/or weak tensioner spring as the culprit.

Trouble is, about six weeks before that I had the alarm system put in. My fear is that they messed something up and I have a slight short somewhere draining the battery. Six weeks before that was my break-in and the steering column fiasco, so that might be in play as well. I would rather have just about any other problem than an electrical one... :blah:

 

[uss2defiant]

Might want to email Josh the parts guy to confirm that part.

I replaced mine with a Gates belt tensioner which had both pulleys on it. Maybe that MOPAR part number could be the whole assembly.

 

[profdlp]

...Maybe that MOPAR part number could be the whole assembly.

I used the Mopar number to cross reference it and look at a few more pictures. Most of the sites showed the whole works. I just ordered it 45 minutes ago so in a few days I guess I'll find out.

 

[LibertyTC]

You should be just fine with the Mopar Tensioner.
I replaced mine with a Gates 39120 assembly and also gates belt both 76mm pulleys.
Now Steve with that fancy 2007, may have something else unique...LOL...
The Gates 39120 comes with a new bolt as well.
My Thread with all kinds of info / pics can be a fun read ha ha..
http://www.jeepkj.com/forum/f196/jeep-kj-liberty-gates-tensioner-belt-56405/

 

[Cardhu]

the gates tensioner fits the 2007, replace the whole unit. My old belt had stretched a lot. I mostly blame the ATF 4+ in my power steering + the temps i see up here with blown PS hoses to prove it.

 

[profdlp]

I got home from work tonight and decided to pop the hood and have a look, mainly to see if I could clear up the confusion over tensioner and pulley. (Which I would assume is part of the tensioner.) Guess what - my serpentine belt is HALF GONE!!!

That's right, it is essentially split in two and instead of being an inch wide it's down to about 1/2 an inch. When it separated it apparently beat the crap out of the hood liner, which now has a big torn groove right above the belt location.

Here's the thing: I just changed my oil about three weeks ago and I know it was fine then. I was under the hood checking it every couple days for a few weeks after that and I'm sure I would have noticed a problem right away, so this must be very recent, as in the last couple of days. On a side note, there is some kind of white milky crap all over the new oil filter. It looks more like something spraying up from the road than anything else. The oil level is good and there is absolutely zero loss of coolant, so I'm figuring this is unrelated. Tell me if I'm wrong about that.

Anyone know what could have caused this? I don't get home from work until about 11pm so it's hard checking things out with just a flashlight. I am praying that what's left of the belt can hang in there until the new one arrives. I was hoping it would get here by the weekend so I could do it then. Now I'm afraid it may not hold out that long. If the rest of the belt goes am I in danger of doing any damage to the engine?

Oh, crap. Woe is me... :emotions34:

 

[uss2defiant]

my other guess would be ATF

 

[profdlp]

my other guess would be ATF

If you're referring to the stuff on the oil filter, I wiped a spot clean to see if it returns. I have to drive through about five miles of construction twice a day to and from work. Having had another look at it I think it might be concrete dust which has been hosed down, then got sprayed up under it from below. On the other hand, there isn't a lot of it sprayed anywhere else...

 

[uss2defiant]

I was fortunate to catch my serpentine belt split parallel to the ribs like yours before all hell broke loose.
Glad that was the worst of it.

I noticed this tool at brakemasters last week for epdm belts.

You must be registered for see images attach

 

[profdlp]

I am hoping that mine was just worn. What would I look for if it was something else causing it?

 

[uss2defiant]

I am hoping that mine was just worn. What would I look for if it was something else causing it?

Not sure. My guess would be the pulleys may not be aligned.
After going through some paperwork this week, my wife had that split belt changed back in 2012. It split last summer. x.x

 

[uss2defiant]

looks like Gates designed a new tool.
Get it free from here

Gates Belt Wear Gauge For Serpentine Belts | Gates Corporation


Woot! free stuff!

 

[profdlp]

Not sure. My guess would be the pulleys may not be aligned.

How would I check? With a straight edge? That's how we did it with A/C pulleys and belts back when I was into that, just lay a level across the flat edges and look for gaps.

After going through some paperwork this week, my wife had that split belt changed back in 2012. It split last summer. x.x

So two years and done? Was that due to misaligned pulleys?