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relsoc 01-25-2010 09:56 AM

Belt Tensioner & Idler Pullies...
Dropping the Tribeca off at the dealer tonight. The Belt Tension and Idler Pullies are both making horrible noise. Just hit 65,000 and have Gold Extended warranty that covers them. Anyone else have this issue? Just curious. I need to get it back for the 60K service as soon as the tax refund hits the bank. :)

legandrex 01-26-2010 09:30 AM


Originally Posted by relsoc
Dropping the Tribeca off at the dealer tonight. The Belt Tension and Idler Pullies are both making horrible noise. Just hit 65,000 and have Gold Extended warranty that covers them. Anyone else have this issue? Just curious. I need to get it back for the 60K service as soon as the tax refund hits the bank. :)

I hear some noise at startup(few minutes) but it goes away. Same thing? We have 56,000 miles on ours.

relsoc 01-26-2010 10:35 AM

Anything is possible. When you start the vehicle cold, take some WD40 with the spray nozzle close to the tensioner pully and zap it with some lubricant. If it stops and then comes right back then its that pully.

nuKe 04-28-2013 12:48 PM

3 Attachment(s)
Replaced the belt tensioner idler pulley bearing yesterday. Was grinding but not bad enough to seize yet. Thought it would be a good idea to save my belt or being stranded somewhere upon the battery dying. Actually thought it was the alternator with a bad bearing but a listen through a mechanics stethoscope narrowed the source.

After some reading over at went out and bought a bearing from NAPA.
Part number on original bearing: NSK 6203DUL1
NAPA part number: SKF 6203-2RSJ
Considering subaru list the part a complete assembly @ $100 and the replacement bearing was $8 i think the direction was clear.
Knocked out the old and CAREFULLY knocked in the new, wasnt pressed in too tight!
Remember to be careful not to use the inner sleeve or the rubbers to install, only the outer sleeve (see pics) i actually used a combination of the old bearing and a socket to get the new one in.

As mentioned in the thread link above, make sure you dont lose the nut which is at the back of the idler when removing it from the tensioner.
Also, the washer needs to be reinstalled the same way around because it is slightly flanged (also has some nubbs outward facing). If installed the wrong way it will freeze the idler and then you be up for a serpentine belt aswell.

Another $90 savings! BONZA!!!!

avk 04-28-2013 02:55 PM

subaruoutback also has a mention of Dayco 89007 pulley, which is a little smaller in diameter but works fine, and costs only around $10.

nuKe 04-28-2013 03:29 PM

Yes I did see that and am sure it would be fine. The diameter of the pulley wouldnt matter much unless overly or underly only applies pressure to the belt to take up the tension.
I opted for the bearing because I could get it the same day and it wasnt pressed in with a huge amount of force.
Reading that thread is beneficial though to give someone alternate options.

tribecadean 05-05-2013 11:36 AM

I have bearing noise
mine Sounds noisy in the pulleys.

1- I dont know where to start,as I dont know which one it is.

2- access is seems like a knuckle buster as its so close to the rad.

I would like to do it myself, but I need some guidance. any pictures or steps out there?
thanks for any help

tribecadean 05-05-2013 11:41 AM

I saw the link on directions: So I will go study that.

nuKe 05-05-2013 11:58 AM

To narrow down which or where it is coming from you can use a LOONG screwdriver. With the engine running and the noise present, hold the tip on the pulley bolt (or any non-moving part for that matter) and put your ear on the rounded handle end.
Yes it is tight but the main problem was the radiator hose, luckily it is flexible enough not to be that big of an issue.
Remove the plastic cover at the top of the grille for better access.

tribecadean 05-05-2013 04:17 PM

replaced the idler and tensioner pulleys for $40.
bad tensioner pulley- once i got the belt loose ,it had wobble and a rough spot in the bearing,I went ahead and replaced the idler ,next to it.

on the outback forum, they said a dayco 87009 steel pulley/bearing assembly from advanced auto parts will fit, $20 each and 40 for the pair.

I put a pair on, it was pretty easy. i will post photos.

as nuke said: dont get the flanged washer flipper that holds the idler ,or your idler will bind.

also: somebody said: stuff a rag behind the tensioner bolt hole/bracket to hold the nut in.I did that and the loose nut on the back of the bracket stayed put.

you need a short 14mm socket and 18inch breaker bar to loosen the belt and to also remove the two bolts.

I bought a $9 breaker bar and a $12 kit of short sockets. so I fixed the car for $75 total.:D :D :D :D :D :D :D :D :D

thank you ALL! engine sounds sweet!

tribecadean 05-05-2013 07:07 PM

steps from other site- subaru outback forums
5 Attachment(s)
here is my install of pulleys.
1- tie down belt , loosen with a 14mm short socket aand breaker bar bar pulling towards drivers side.
2-i looped loose belt up thru a dowel rod to keep it in place.
3- STUFF Rag behind tensioner- DAMN GOOD TIP!!!
4- take off pulleys and look for washers on floor.
5- put on new TWO dayco 89007 pulletys from advanced auto parts
6- make sure pulleys spin freely when tight.
7- reinstall belt- as you pull on breaker bar.

hope this helps for beginners like me.

tribecadean 05-05-2013 07:48 PM

helpful post on tensioners
2 Attachment(s)
here is some help. Stuff that helped me.

nuKe 05-06-2013 05:09 AM

Awesome! Glad it worked out for you and both jobs done for less than the subaru listed tensioner assembly itself. + you have some tools for the next job :D

Esoobee 12-24-2014 08:56 AM

Hi, getting going on this job and trying to do something good before I do something baaad. Do the bolts that mount the idler pulley (not the tensioner pulley), and the tensioner pulley assembly to the engine have standard thread orientation? I know that the tensioner pulley is threaded reverse. Just don't want to twist anything off on Christmas Eve, except a Champagne cork!

avk 12-24-2014 09:03 AM

There are no left-handed threads anywhere.

Esoobee 12-24-2014 09:09 AM

boom. thx. And Happy Holidays!

rickst29 01-10-2015 08:27 PM

I just replaced the entire Tensioner Assembly in my 2007,
at 80K miles, using "Delco 38489" (the exact same part as OEM for $38), along with a compatible (but not identical) idler pulley for about $30, and a new V-belt (just over $20). The bearing inside the Ilder Pulley was pretty bad, causing a bit of wobble and a lot of noise, and the bearing inside the Tensioner Assembly Pulley was even worse.

I'm planning to do the next swap-out at 140K (just 60K miles more). So Subaru's 105K schedule seems very risky to me - and you can't really judge the pulleys until you've removed the belt, at which point you might as well replace both Pulleys anyway. The belt is only about $20.

Now comes the interesting part of my post:

This first replacement leaves me with a "spare" OEM Tensioner Assembly (consisting of a spring assembly, plus the spring-loaded "pulley mounting assembly" portion, which includes a nut to accept the pulley bolt, plus a pulley assembly (bolt, washer, pulley, and replaceable bearing) which is 100% identical to the idler pulley. The "Tensioner spring assembly" base and the "pulley mounting assembly" (on the other end of the spring) both seem pretty good after 80K miles.

The OEM Pulleys, bolts "T4", and "pulley cover" washers appear to have enormous lifespans - if you simply change the bearings. So... with the new parts and V-belt installed, I just used an 18mm socket and sledge hammer to "press out" (err, with slight violence) the old, worn-out bearings. Then I cleaned the gunk of the bearing sockets in the pulleys, and used the socket and sledge hammer to (slightly more gently) "press in" new bearings to full depth. (I bought USBB "premium" 6203RS bearings with pretty blue seals, at $10.98 for a 4-pack off EBay, at the same time I ordered the a new V-Belt, replacement Idler pulley assembly, and new Tensioner "assembly" with everything.)

Next time, instead of buying $15-30 Idler and Tensioner "pulleys", I'll just re-use the removed pair of my old ones - with new bearings each time. About $26 total for new V-belt and bearings on each future "Pulley and V-belt replacement" job. It's about 30 minutes total, as long as you're not wrestling with the "T2" bolts on the Tensioner Assembly "base". A lot less time than writing this detailed post. :) With my relatively low-RPM driving, I feel pretty good about the risk of running the Delco Tensioner spring "assembly" through AT LEAST two generations of pulley bearings replacements, up to age 120K (maybe even 180K) on the Tensioner spring before I buy another Tensioner "assembly". YMMV, of course.

Esoobee 01-11-2015 06:47 AM

Great post and prep for the next round Rick. My job went well and the car runs great. We had been noticing hesitation on acceleration and passing for a while. That is completely gone and the car has a lot more pep than before. Guess there may have been some belt slipping or something going on.

I just made the job easy on me (although more expensive) and purchased the oem parts out of the box. I'm going to do it the more cost effective way next time.



tribeca09 02-16-2015 12:07 PM

40k mi. and pullies toast. WTF!
The title says it all. With all I've read about these parts failing at such low mileage, they should be issuing recall and at a minimum a TSB.

My wife's '10 Forester also went in for the brake line "coating" "repair" -- actually more like a band aid solution, and they told her to come back in because they didn't apply the coating correctly the first time.

I can now say I tried it, and I'm done w/ Subaru. :mad:

The pulleys I'm using for replacement are NAPA/Gates 36330 (idler) and 3849 (tensioner assembly). The idler is a nicer piece than OEM. Nobody lists the tensioner pulley alone and I'm not about to use anything other than what's listed in the off chance Subaru would claim I've ever used incorrect parts. The original idler and the tensioner pulleys are NOT the same size as one another, contrary to what it seems some people have suggested.

avk 02-16-2015 12:29 PM

The two factory pulleys are both 80 mm in outer diameter.

tribeca09 02-16-2015 12:37 PM

"The two factory pulleys are both 80 mm in outer diameter."

Like I said, no they are not.

The tensioner pulley is 3/8" smaller, and that is not a small difference.

Dodik 02-16-2015 12:47 PM

Not sure why they are not the same on your car, but on mine they were the same 09 tribeca, as well as my old 2002 H6 outback.

avk 02-16-2015 12:49 PM

This contradiction appears difficult to explain, but I am sure it has to be something simple. FWIW, I have a spare tensioner unit (same part number for all 2006-14) and it has a 80 mm pulley.

tribeca09 02-16-2015 12:59 PM

That is bizarre.

The replacement idler pulley (Gates 36330) is the same as the original idler pulley, which measures approx. 80mm. And that is the correct part no. for the idler pulley.

I can find no replacement part no. for the tensioner pulley alone.

The original tensioner pulley is approx. 70mm (or 3/8" smaller than the original idler pulley).

I'm picking up a replacement tensioner assembly (38489) in an hour and should know more then.

Oddly, the only model years for which any tensioner pulley assembly is listed is through 2007 (i.e., 3.0), not beyond (i.e., 3.6). That was the case at NAPA and at

tribeca09 02-16-2015 01:26 PM

Are we sure that the tensioner assembly is the same for 2006-2007 and 2008-2014?

I am finding different Subaru part nos. for the two different series of model years.

For 2006-2007, I come up with 23769AA003, 000, 001, 002.

For 2008-2014, I come up with 23769AA010.

The 38489 replacement tensioner assy. measures 80mm according to the specs online. And it seems to show up for 2006-2007 model years.

I'm wondering if the tensioner assembly changed in 2008-2014, with the switch from 3.0 to 3.6 liters.

Dodik 02-16-2015 01:34 PM

my old 3.0 outback 2002 also had same size pulleys, in fact the first time i was doing them i bought two pulleys and just reused the tensioner.

tribeca09 02-16-2015 01:38 PM

I'm heading over to the dealership parts counter now and will post back. They have the part (determined using my VIN and the part no. ending in ...010) in stock.

tribeca09 02-16-2015 02:11 PM

I just returned with the new Subaru tensioner pulley assembly. It is P/N 23769AA010 and the tensioner pulley itself is approx. 70mm, identical to my original tensioner pulley.

Bottom line, I believe that the 2008-2014 model year (i.e., 3.6 liter) tensioner is different from the 2006-2007 model year (i.e., 3.0 liter).

The belt sizes appear to be different across those MYs too.

tribeca09 02-16-2015 05:16 PM

Can't say for sure, but it might be worth it to somebody, for the 2008-2014 model years ONLY, to try, for the 70mm tensioner pulley ONLY, Dayco 89175, Gates, 36301, or Gates 36174.

The OEM tensioner pulley and these steel pulleys all appear to be approx. 70mm OD x 17mm ID x 33mm Wide (or, in the case of 36301, 33.5mm).

Next time I have to do this again I'll probably try one of these ... hopefully by then somebody else will have confirmed their utility.

avk 02-17-2015 06:30 AM

Indeed the tensioner is different between 3.6 l and 3.0 l engines. I believed aftermarket catalogs showed the same part (which in this case would be OE anyway), but my memory failed me. Yes, a generic 70 mm pulley would be a perfect match.

rickst29 02-21-2015 07:52 AM

That theory fits my B9.
My 2006, 3.0L came with totally identical OEM pulleys (both large).

And tribeca09, thanks for posting your findings about later model years. My recommendation "every 40K miles" would have prevented even the earliest of failures which have been posted here, and on equivalent Outback forum - but I'll SWAG that a 60K schedule would also catch about 90% of failures as well. I also wonder how many failures have been prevented by more knowledgeable, competent technicians checking not just the belt, but the pulleys as a part of 30K/60K/90K "check the serpentine belt" scheduled Service. (Possibly many hundreds.)

I'm unsure why the Subaru 3.0 and 3.6 Boxsters are "more prone" to this failure than other cars which use the same pulleys, and even the same tensioner assembly. (Several GM models, IIRC.) Perhaps the Subaru design has the belt path more fully wrapped around the pulleys, with corresponding higher "sideways" tension on the bearing. (Because the belt route around the pulleys is placed further from a "tensionless" straight-line belt path in our cars, comapred to the GM cars.)

tribeca09 03-15-2015 06:15 PM

I picked up a Dayco 89175, which does appear the same as the 09 MY 70mm factory tensioner pulley. I'm going to keep that, a spare Gates idler pulley, and my old belt in the trunk in case the pulleys begin to make noise on a long trip. I'm also planning to replace them both routinely at 40k miles, which is completely ridiculous but I'd rather that than have them seize unexpectedly.

I got to install some band clamps around my exhaust shields today too. LOL, you'd think these cars are made of metal that is engineered to fail. If my 40 year old Chevelle had airbags I'd drive that daily instead.

tribecadean 03-21-2015 06:22 PM


Originally Posted by tribeca09 (Post 22726)
I picked up a Dayco 89175, which does appear
I got to install some band clamps around my exhaust shields today too. LOL, you'd think these cars are made of metal that is engineered to fail. If my 40 year old Chevelle had airbags I'd drive that daily instead.

I had a temp fix too on my exhaust shields , I like your idea, I took my 06 up to midas and had them weld them...seems like it was 50 bucks or so. been fine ever since,

tribeca09 03-22-2015 10:34 AM

I didn't have the correct size so I used 2 stainless worm style clamps I had from another project, attached them end to end and they fit fine. I did the other heat shield too because it was just a matter of time. I didn't crank the clamps tight, just snugged them enough to cure the rattle.

milo066 04-22-2015 11:29 AM

Replaced the Tensioner and Idler pulleys in my 2006 B9 with the Dayco 89148 as recommended on the Advance Autoparts website. They are spec'd at 82mm and the same as both taken off in that respect. Their construction is different and they are chromed, not what I am used to or like the ones I took off. Advance offers an OEM spec on their website for delivery to you, not available at the store. I'll do that next time (Litens Pulley 900558A). I bought 2 new washers at Subaru for $2 each just for the heck of it. One of mine was galled from the Tensioner pulley having frozen. Was a simple job, thanks to the Rag tip! Boy I am glad I read this forum before I took the pulleys off! As for the 70mm pulleys, it would have made getting the belt on a little easier but realize the smaller diameter will spin the bearings a smidgen faster than the 80mm version. Also makes the U-turn of the belt a bit easier flex wise...

avk 04-22-2015 08:28 PM

70 mm is for 3.6 l engine, the dimensions are not identical to 3.0. The Litens unit looks like another aftermarket alternative but not identical to the factory part.

Dodik 04-23-2015 07:05 AM

why is everyone replacing pulleys, it takes 5 min to swap new bearings in and they are much cheaper.

psygnal11 04-24-2015 06:18 AM


Originally Posted by Dodik (Post 23025)
why is everyone replacing pulleys, it takes 5 min to swap new bearings in and they are much cheaper.

Agreed. Timken 203FF -or- SKF 6203-2RSJ. No need to replace the whole idler unless it's damaged/deformed.

singincanary 05-02-2015 08:54 PM

Without a press it is difficult to replace just the bearings.

avk 05-03-2015 11:29 AM

A hammer and correctly sized sockets seem sufficient to apply the necessary force in this case, but on the other hand, generic pulleys are easy to find under $15.

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