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Belt Tensioner & Idler Pullies...

45K views 74 replies 28 participants last post by  jimihimisimi 
#1 ·
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. :)
 
#28 · (Edited)
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.
 
#29 ·
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.
 
#30 ·
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.
 
#31 · (Edited)
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.)
 
#32 ·
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.
 
#33 ·
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,
 
#34 ·
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.
 
#35 · (Edited)
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...
 
#41 ·
I just finished replacing my tensioning and idler pulleys on my 2006 Tribeca. I used the Dayco #89007 serpentine pulleys from advanced auto parts. The tensioning pulley had seized while we were in the mountains here in Colorado and it was a Sunday so we had the vehicle towed home. There was no indication the pulley was going bad, just a little squeaking at start-up that went away in about 10 seconds. I learned the hard way on this one.

Thank you to all members of the forum who contributed to this thread, with all the useful information. Rag stuffed behind the tensioning assembly, Brilliant! I will press out the bearings on both pulleys removed and replace them per instructions given here, and have two good spares for next time. God bless you all.
 
#43 ·
They are both SKF 6203-2RSJ for the 3.6L pulleys.

I had two ACDelco 36330 Professional Idler Pulley that I got on amazon for $26/ea. The tensioner is smaller on my 3.6L but I could get the new belt on with the tensioner compressed fully. I didn't like that so I got the Napa SKF bearing. After pressing it in, I like the feel a lot better than the ACDelco which has a good amount of wiggle and will press in a new bearing for my idler.

I don't know where people are getting the $5 bearings. I couldn't find it for at Advance (they tried to sell me one with a metal seal, which doesn't have as good of a seal as the rubber) and NAPA took me for $15. Ebay the cheapest one I see is $10. I see some no-name brands on amazon for $5 but lots of reviews that said they failed.


I'll satisfy my need for immediate gratification by picking up a new one at NAPA tomorrow.
 
#49 ·
Replaced mine last Saturday. 128K miles. 30 minute job. You need a puller set-up (sockets and threaded bar, nuts and washers. Make sure you only press on the outer diameter of the bearings, on the metal only. NOT on the seal. So socket size selection is important.

Both removed bearings were shot and basically seized. New OEM belt installed.

McMaster part number 5972K44
Ball Bearing, Double Sealed, for 17 mm Shaft Diameter, 40 mm OD
$6.18 each plus shipping. Made in S. Korea. Good quality.
 
#53 ·
Replaced tensioner pulley bearing today. Had idler pulley fail dramatically about a year ago resulting in breakdown at roadside. At that time, not knowing any better, I replaced entire pulley. The tensioner pullley at that stage was in good condition. A few days ago, I got a warning that this pulley was about to fail. When turning corner, the steering became heavy and battery light came up. There was also a short squeal from v belt, presumably as it was slipping on the seized pulley. Luckily, the pulley freed itself.

Recognising an imminent pulley failure, I looked at the options.

1. New tensioner - £90 for aftermarket and I would guess £200 for genuine.
2. Just replace pulley. Couldn't find one for sale in UK.
3. Replace bearing only.

After reading this thread, I did 3. So glad I did. £5 for bearing and about 30 mins work to swap over (without a press).
Highly recommended cheap fix for both tensioner and idler pulleys.

I bought SKF 6203-2RSH. Most quote 6203-2RSJ but I couldn't find this. The 2RSH fitted perfectly.
 
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