Tensioner Shot? (not decoupler)

darinb · **Posted:** Wed Jan 04, 2012 3:33 pm

My Libby is shredding the edge off the fan belt and now throwing the fan belt off when starting. It looks like the tensioner is leaning outward pretty far but the bolt holding it on appears to be tight. Is my tensioner shot? Is there any way to fix it other than buying a new tensioner??

I have replaced the alternator pulley at around 85k. I put a screw driver against the tensioner while running and it sounds like the pulley bearing in shot.

Thanks!

papaindigo · **Posted:** Wed Jan 04, 2012 6:13 pm

Sounds like the bearing is shot and I don't know that it can be replaced or if anyone has tried. Unfortunately that tensioner is not cheap.

Billwill · **Posted:** Thu Jan 05, 2012 9:38 am

Are the idler pulleys not basically the same pulley and bearing as the tensioner pulley but cheaper?
I am sure that I saw a post about buying the idler pulley and using that to repair the tensioner pulley.

papaindigo · **Posted:** Thu Jan 05, 2012 10:40 am

Billwill - you might be thinking of viewtopic.php?f=5&t=64200&p=708616&hilit=tensioner+idler#p708616 . If your read is correct that's a good catch as I'd overlooked the reference to tensioner and assumed tigafila was just speaking to the 2 serp belt idler pulleys. I'll send tigafila a direct query; if it's possible to repair the tensioner this way it's a big savings as I recall a new serp belt tensioner being close to $200.

Billwill · **Posted:** Thu Jan 05, 2012 1:38 pm

papaindigo wrote:

Billwill - you might be thinking of viewtopic.php?f=5&t=64200&p=708616&hilit=tensioner+idler#p708616 . If your read is correct that's a good catch as I'd overlooked the reference to tensioner and assumed tigafila was just speaking to the 2 serp belt idler pulleys. I'll send tigafila a direct query; if it's possible to repair the tensioner this way it's a big savings as I recall a new serp belt tensioner being close to $200.

I am sure it was tonycrd who posted how you can make the idler pulleys work as a tenshioner

papaindigo · **Posted:** Thu Jan 05, 2012 1:59 pm

Maybe tony did too but I just got a reply from tigafila confirming that the NAPA parts listed in his post will do as replacements for the 2 serp belt idler pulleys and the pulley on the serp belt tensioner. I am awaiting a reply to my query as to how to do the pulley swap; I think I know but am not positive.

If this works and the tensioner is bad because of a bad pulley bearing, not a bad spring, then a $15 pulley from Amazon (free shipping if part of a $25 order) is a whole lot better than a new tensioner at close to $200

Billwill · **Posted:** Fri Jan 06, 2012 2:41 am

papaindigo wrote:

Maybe tony did too but I just got a reply from tigafila confirming that the NAPA parts listed in his post will do as replacements for the 2 serp belt idler pulleys and the pulley on the serp belt tensioner. I am awaiting a reply to my query as to how to do the pulley swap; I think I know but am not positive.

If this works and the tensioner is bad because of a bad pulley bearing, not a bad spring, then a $15 pulley from Amazon (free shipping if part of a $25 order) is a whole lot better than a new tensioner at close to $200

You guys in the USA are so lucky to have access to all of the alternative parts suppliers such as NAPA.....here in darkest Africa we have to get our parts from the dealership at stupid prices.

If it is not an emergency then we can get parts from overseas online....if we know the part numbers......if I need to replace my pulleys sometime I shall look for the NAPA part numbers provided here

darinb · **Posted:** Fri Jan 06, 2012 9:53 am

Thanks for the replys :mrgreen:

I bought an idler puller at Napa (36101) and will try installing it onto the tensioner before replacing the whole assembly. From what I read the tesioner itself is a right hand thread and the idler wheel is left hand.. is that correct?

papaindigo · **Posted:** Fri Jan 06, 2012 12:03 pm

I'm going to go out on a limb here and speculate. There is a good picture of the serp belt tensioner here http://www.keepandshare.com/doc/1729864 ... 8-meg?da=y on page 3. The wrench is on the "fake" 15mm nut machined into the front of the tensioner that's used to rotate and relax the tensioner by rotating the wrench clockwise facing the engine (hold the wrench while removing the serp belt and the slowly let the tensioner return to it's position - DO NOT let it slam back). The bolt to the left is what holds the tensioner assembly to the block so remove that bolt, should be standard counterclockwise to remove, to remove the tensioner assembly (on reinstall the FSM says torque is 47nm which if correct equals ca. 65 ft lbs). FYI at this point you should be able to easily determine if you have a bad tensioner pulley or a bad tensioner. Since the tensioner is essentially a tension spring and pulley the only ways I can see it going bad are 1) loose tensioner retaining bolt; 2) weak or broken spring both should be obvious 3) loose pulley bolt but I don't see that as likely; or 4) bad pulley bearing also obvious. Assuming it's the pulley bearing then from here on I'm venturing a somewhat informed guess. Flip the tensioner assembly over and on the back side of the idler pulley there should be a retaining bolt (parts manual appears to call it a "screw"). Since the belt rotates that idler pulley counterclockwise as viewed from the front then when viewed from the back the rotation direction is clockwise so I "think" this bolt should be a standard counterclockwise to unscrew. Replace the bad pulley with the new one minus the dust shield or what tigafila refers to as the large washer. I have no clue as to the correct torque and can only observe that the 2 serp belt idler pulleys, per the FSM, are torqued to the same spec as the tensioner retaining bolt.

Reassemble. Crank up engine and observe behavior of serp belt at idle. If it's steady and tensioner is not bouncing your good to go but I'd keep and eye on things for the next 3-400 miles just to be sure.

darinb · **Posted:** Mon Jan 09, 2012 4:51 pm

I had a chance to tear into it this weekend. I took the pulley off the tesioner and the bearing seems fine. The pulley is indeed a right-hand thread. I noticed that my tensioner is pressing against the large pulley right below it. I took the bolt out that holds the tensioner to the block and could not get the tensioner past the large pulley below it. Do you normally have to remove the assembly with the large pulley below to get to the tensioner? I'm not sure what it is.. maybe power steering pump. I didn't look to closely.

papaindigo · **Posted:** Tue Jan 10, 2012 9:15 am

FSM says to simply undo the bolt holding the tensioner to its mount and remove. I suspect that in the relaxed position the tensioner may contact the power steering pump pulley but don't know if that is normal or not or if there is some way to lock the tensioner to keep it from fully relaxing.

ibedonc · **Joined:** Mon Feb 12, 2007 2:40 pm **Posts:** 236

darinb wrote:

I had a chance to tear into it this weekend. I took the pulley off the tesioner and the bearing seems fine. The pulley is indeed a right-hand thread. I noticed that my tensioner is pressing against the large pulley right below it. I took the bolt out that holds the tensioner to the block and could not get the tensioner past the large pulley below it. Do you normally have to remove the assembly with the large pulley below to get to the tensioner? I'm not sure what it is.. maybe power steering pump. I didn't look to closely.

you will have to remove the power steering pulley and replace the whole tensioner , mine did the same , it was separating and rubbing the PS pulley , destroying the belt

darinb · **Posted:** Wed Jan 11, 2012 11:12 am

Thanks for all the help. I ordered the tensioner for $175 and another napa pulley so both idlers will be new. Hopefully it will be running smoothe again once I replace the belt.

Coopin · **Joined:** Tue Dec 03, 2013 2:55 am **Posts:** 8

My tensioner also failed and I thought I was in for replacing my power steering pump. Thanks to this discussion I didn't buy an overpriced power steering pump and I was able to find a tensioner on line for $69 bucks! Thanks for your posts!!

Srytrucker · **Posted:** Tue Jan 28, 2014 1:17 am

I used the idler pulley on tensioner and it has been working smooth for 10k Km.

DOC4444 · **Posted:** Thu Jan 30, 2014 9:42 am

Did you press out the right hand thread bolt and reuse the left hand thread bolt for the tensioner pulley?

DOC

Tensioner Shot? (not decoupler)

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