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Idler Pulley/Bearing Failure, what to do:

296K views 248 replies 116 participants last post by  darksidetourist57 
#1 · (Edited by Moderator)
I know this has been discussed in many threads but it got difficult to sort though all of it so here is what I could gather.

First, THANK YOU to everyone that has been putting in so much work to figuring all of this out over the past 4 years!

OK, here goes...

As most of you know, the factory Toyota bearings inside the idler pulleys on the FJ are not sealed... go figure.

What does this mean?
Well, if you do any type of water crossing or playing in the mud, it could potentially get dirt into these bearings and sooner or later they will start to go bad.

How do you know if you have a bad bearing?
The first clue is a 'screeching' noise coming from under the hood, usually a couple of days after a water/mud crossing. Most likely, the noise will start to get louder and louder with time and RPM. In some cases, the problem has been with other pulley bearings as well, such as the alternator, power steering, etc... however, in over 90% of the cases, the bad bearing(s) will be in the idlers (usually uppers).

How to prevent your bearing(s) from going bad?
Next to staying out of water and mud, there really isn't a sure way of keeping the pulleys from going bad. One thing that has worked for sometime is to 'wash' down the idler pulleys after wheeling. Take a small water bottle and punch a hole into the top so that you can 'squirt' the water at the pulleys, usually works very well. Also, here is a write up on how to properly clean your pulleys:https://www.fjcruiserforums.com/forums/how-technical-articles/39749-pulleys-proper-cleaning.html This requires disassembly of the Serpentine system.

OK, OK, what bearings, in what pulleys are we talking about here really?
There is some confusion, not only on FJ forums but also in the different manufacture year manuals, as to what idler is 1, 2 and 3, so for the sole purpose of this write up, I will stick to the terms, 2 uppers (Pictured as #2 ) and 1 lower (Pictured as #1 ).

In this diagram, taken out of the 2007 FJ Cruiser Manual, the 3 idler pulleys are circled in red along with the belt tensioner circled in orange. All 4 of these pulley bearings are not sealed and could potentially get damaged in a water/mud crossing.


What to do if your bearing(s) are bad?
If you still have warranty on your truck, take it in! Usually the dealer will replace the idler pulleys at no charge under warranty.

If that does not work, or your out of warranty (like me) then I'd suggest at looking for sealed bearings/pulleys.

The factory non-sealed pulleys are Koyo.

ACDelco, Dayco, Gates and Goodyear, all make sealed idler pulleys for the FJ or at least they claim to. After looking at some of the aftermarket pulleys, it appears that most (if not all) use NTN Canada Bearings. If its the same bearing for all companies, I do not know.

One issue I have run into personally, is that the aftermarket bearings require a sleeve (bushing, spacer, or what ever you want to call it) in order to work properly on the FJ however, some (like ACDelco) make an incorrect sleeve and others do not have one at all...

The correct sleeve for the upper, should be around 0.405" ID
(I do not have the measurement for the lower at this time)
In any case, there should be almost no play on the bolt what so ever!

So which pulley(s) do I buy?
Great question and really what this thread is all about! My recommendation is Gates! Why, I have had good luck with Gates products in the past and from reading a lot of threads about this issue on different FJ forums, most agree that Gates is the better choice.


Gates:


Two Upper Pulleys (#2 ): 36173 Product Detail Page
One Lower Pulley (#1 ): 36174 Product Detail Page
Tensioner: 38411 Product Detail Page
Serpentine Belt: K070834 Product Detail Page

[Added by Winterpeg]
NAPA part numbers:

Here are the part numbers for the NAPA pulleys....
drivebelt idler pulley, lower - UNR 36174 - $ 112 CAD
drivebelt idler pulley, uppers - UNR 36173 - $ 93/each CAD
drivebelt tensioner assembly - UNR 38411 - $ 184 CAD

American napa uses NBH as the line code rather than UNR
The actual numbers are the same.

Where to Buy?
You can get the parts where ever you want but the best deal so far that people have found is from RockAuto. Their prices are great and with one of the Coupon Codes from RetailMeNot you can safe an addition 5%.

Tensioner Pulley Warning!
Apparently the upper pulley part number cross references as the pulley on the tensioner and some have ordered just the pulley instead of the entire assembly. After further research (not by me) it turned out that this was not the case and that the pulley did not work. Apparently the spacing and dimensions are incorrect. My suggestion is just to replace the entire tensioner assembly and avoid any potential damage that could occur by installing the wrong pulley.

How to determine which one is bad?
When the engine is running, carefully look at the pulleys and see if any of them is 'wobbling'. If that does not work (and usually its not very accurate), with the engine off, undo the tension on the serpentine belt and spin each tensioner individually. Usually you can tell which one is bad by a rapid stop, a wobble, squeal or anything out of the ordinary.

Disassembly:
If you've never worked on a Serpentine System before, please have someone help you that has. It is not complicated by any means however, any misalignment of the belt could cause serious damage to parts, you and the engine. Also, be careful working with the tensioner and around the radiator fan!

I'm not going into to much detail, anyone working on this should know how to do this.

To loosen tension, just rotate the tensioner counterclockwise (to passenger). There is a little loop at the bottom you can put a allen wrench in to hold the tension while your working.

The pulley bolts are fairly tight but should break loose with a good wrench or breaker bar.

Here is a picture of my two upper pulleys, the black ones are the new Gates (notice the sleeve that comes with them on the left side) and the silver ones are my old factory ones (Koyo):


On the factory setup, the two upper pulley bolt actually has a 'dust cover'/washer on it. I did read that some did not install it again but after a good cleaning and taking some measurements, I decided to put it back in. The center riser is a perfect fit on the sleeve so it will not damage the bearing and the OD is just perfect to sit inside the pulley, here is a picture of the parts:


At this time, I have only replaced the two uppers, mainly because my tensioner and lower idler are still in good condition and unfortunately both are currently on backorder. I will update this thread once I can get my hands on the lower and a tensioner.

EDIT: For Tensioner Pulley Replacement please refer to post 3 in this thread by 5Greens: https://www.fjcruiserforums.com/forums/maintenance-tech/127154-idler-pulley-bearing-failure-what-do.html#post1888318

Installation:
Do what you just did in reverse. Seriously tough, it is very easy to loose the sleeve or washer during the process. My recommendation is to put it together outside the vehicle (insert sleeve into bearing, lay the washer on top, insert bolt). Once in place, tighten by hand until snug (make sure that the bolt is 'inside' the pulley to confirm that the sleeve is set in all the way).

Now torquing to 'factory specs' is an entire debate in itself! Apparently there are variations in the different manufacture year manuals.
My FJ is a 2007 and out of my 2007 manual this is what I got:




Rout belt, double and triple check to make sure that the belt is perfectly routed and seated on all pulleys. BTW, if you did not replace the belt (I'd recommend replacing if you have more than 70K on the truck) please check for damage before installation!


To conclude, part numbers and torque specs (2007 Manual):


Again, I will update with any information I and/or others have.
 
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#35 · (Edited)
Here are two files with info on the belt installation. Installing a new belt is not a difficult job. It requires a bit of patience working in the crowded environment at the front of the engine. You can go at it from the bottom by removing the skid plate or through the topside. I went through the top. Just be very careful to make sure the belt is properly aligned on all of the pulleys before starting the engine. Any misalignment could easily ruin the new belt. Check and double check by feel and not just visually. It took me about 20 minutes including the checking.
 

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#36 ·
Ok, great post. I replaced all of the pulleys and the belt and had no problems doing so other than the lower alternator bolt being hard to get out. But after driving for about an hour of driving the ringing/ whining sound came back. It used to only do it when I was driving at low speeds and I would hit the gas, but now I can even hear it when I am coasting and it is still intermittent. I have an automatic 07 with 110,000 miles.

Sent from AutoGuide.com Free App
 
#39 ·
Are you sure you replaced all of the pulleys?
Can't imagine the rear end making noise while you are out of the FJ and stopped, especially if you are describing the noise getting louder when accelerating.

I changed my belt about a month ago and it just started making noise last week when accelerating, the noise is definately coming from the pulleys (front end). Will change them soon.
 
#40 ·
There's nothing in the back end of the FJ that would be making a whining sound similar to a bad pulley when the FJ is not moving (except maybe the EVAP test pump but that typically runs after the engine has been shut off for a while.)

Maybe you can sleuth around a little more as to the source of the noise.

DEWFPO
 
#41 ·
After the crazy rain storms, mine is now making noise. I read this thread and started looking at the pulleys...they look like crap.

Especially the one on the generator...but looking at the diagram, its now one of the pulleys...its apart of the generator? I tried to spray some water into it and it quieted down for a bit, then started to make noise again. I also tried WD-40, and didnt help much.


This one didnt look too bad.


The one at the bottom is hard to take a picture of, it looks even worse than the one on the generator...

So..can I replace the one on the generator or do I have to get a new generator?...confused.
 
#43 · (Edited)
To add a bit more info to this thread... For those interested, I've learned the bearings in the Toyota Idler pulleys can be replaced (just did mine a couple weeks ago)... They're about $15 ea (or less) for quality dual rubber sealed NSK, SKF or other bearings. Just hammer out the old dead bearings, and carefully press in the new ones taking care not to press on inner race, or seal. The only additional piece you need, like the Gates aftermarket pulley, is a sleeve to adapt the larger ID bearing for the 10mm mounting point.

Idler Bearing SKF PN: 6302-2rsc3 (needs 15mm to 10mm Adaptor sleeve) Dimentions: ID:15mm, OD:42mm, Width:13mm

Auto Tensioner Bearing PN:NSK BD17-31DUM (exact OEM replacement)

Haven't done the bottom Double bearing yet, but I'm sure it's replaceable too.

So, keep all your pulleys, buy bearings and carry pre-made ready to go replacements on teh trail for you next outing...


Hope this info helps.

Cheers!
NK

EDIT: I should note, the Bearing PN's above apply to OEM Pulleys on a 2007 model FJ. For some reason, I noted when I bought them as well, that the Gates pulley bearings are slightly different dimensions...
 
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#159 ·
To add a bit more info to this thread... For those interested, I've learned the bearings in the Toyota Idler pulleys can be replaced (just did mine a couple weeks ago)... They're about $15 ea (or less) for quality dual rubber sealed NSK, SKF or other bearings. Just hammer out the old dead bearings, and carefully press in the new ones taking care not to press on inner race, or seal. The only additional piece you need, like the Gates aftermarket pulley, is a sleeve to adapt the larger ID bearing for the 10mm mounting point.

Idler Bearing SKF PN: 6302-2rsc3 (needs 15mm to 10mm Adaptor sleeve) Dimentions: ID:15mm, OD:42mm, Width:13mm

Auto Tensioner Bearing PN:NSK BD17-31DUM (exact OEM replacement)

Haven't done the bottom Double bearing yet, but I'm sure it's replaceable too...
Where did you find the 15mm-10mm adapter sleeves? I cannot locate them anywhere. And did you ever replace the bearing in the lower (AC) idler pulley? I have mine apart; it's a 10mm ID; 42mm OD; 26mm width.
 
#44 · (Edited)
Just an FYI these pulleys are NOT totally waterproof....well atleast not headlight deep in mud filled silty water proof... my 2 uppers and the tensioner pulley went after trudging through some stuff I really shouln't have.
 
#45 ·
You mean driving in stuff like this?



and almost a month later I have this happen



Or is it because I have 113K+ on the FJ???

Thanks for the thread.. and the great suggestion of repairing the OEM p[ulleys and having spares!!
 
#49 ·
Help ! Replacing idler bearings , got the 3 idlers replaced , can't seem to get tensioner bearing to loosen . And thats the bad one ! Is it reverse thread ?
 
#50 · (Edited)
Bolt just kept turning , never got it off . It is reverse thread ! Ended up buying whole new tensioner .
What a pain !
Redboat
 
#51 ·
Changing the 3 pulleys tomorrow. Went with Gates. The part # for the tensioner said 07-09 so I didn't order that. Does anyone know the part # for the 2010?
 
#53 ·
i just changed out the upper idler pulley and just cleaned one of the bottom ones that looked dirty. i've never in my life been car savvy and now all i want to do is play with my truck and do more stuff to it. i couldn't have completed this job without any hiccups without this post. so thanks so much!
 
#54 · (Edited)
I replaced my idler pulleys over the winter to ward off any evil spirits. I used the the pulleys recommended in this post. I have a 2007 with a supercharger.

This weekend, I ran the air conditioner for the first time. I'm in Idaho and normally drive with the windows down, but drove to Boise requiring some highway miles and didn't want to deal with the buffeting from the wind. This resulted in a ringing sound coming from the engine that only occurred when air conditioner compressor was running. When I returned home, I found that the tensioner for the supercharger belt interfered with the air conditioner compressor as a result of not having enough standoff space due to the new pulleys. I replaced them with the old pulleys and the tensioner now does not interfere.

For those with a supercharger, you may need to add some spacers (washers) to the two idler bearing posts that the supercharger belt tensioner attaches to. You will also need to maintain pulley alignment. I will need to figure this out if I am to replace the two gates idler pulleys, but for now I am running the stock pulleys.

I had heard this ringing before with the defroster, but didn't put it all together then.

When I replaced the pulleys initially, I found that the replacement bearing posts for the supercharger were only inserted finger tight. I removed them and added some thread locker.
 
#56 ·
Mine might be acting up but I can't catch it in the act to determine the location of the death squeal!

All I know is it sounded like a large high-pitched chipmunk or squirrel was caught in a belt and screaming, not the typical belt squeak. This was LOUD but intermittent. It hasn't done it again today to try and catch it in the act!
 
#58 ·
Excuse me, but I was wondering if anyone would know how to tighten a serpentine Belt or how i can locate it (diagram), FJ Cruiser 08'trails team. I changed my pulleys but the belt is loose now and it squeals. i cannot drive it and would like to fix it asap for work. Any knowledge you could pass on to a newb weekend mechanic please?

Al
 
#59 ·
If its loose , you probably don't have the belt routed correctly .
Look at the first post on page 1 .
Redboat
 
#60 ·
I got the three upper and 1 lower pulley but I have a 2012. The ones I ordered are gates and I can't seem to find anything that talks about the 2012 models. Just to confirm, Is one of the upper pulleys the same part number as the belt tensioner? And does the gate pulley require any spacers?
 
#61 ·
Just replaced all 4 pulleys. easy access from the bottom of the engine. the tensioner pulley bolt is left hand thread you have to turn the bolt clockwise to loosen it and remove the pulley.I didn't have to install the whole assembly. i took the pulley from the new assembly and installed it on the old assembly... it was really easy :thumbup:


Shinny


:thumbup:
 
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#62 ·
I didn't have to install the whole assembly. i took the pulley from the new assembly and installed it on the old assembly... it was really easy
I didn't replace the tensioner assembly either, just the pulley on it. I didn't feel like removing the alternator and ac compressor.
 
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#68 ·
+1 I need to know it too, for 2010 FJ.
 
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