Idler Pulley Failure
 

My idler pulley failed today. No squeaking symptoms prior to the failure which has me concerned. Has anyone heard of a pulley failing without any prior noise? It seized hard enough to bend the bolt that held it in place and of course I lost the serpentine belt. Lost power steering, traction control and ABS and the battery light came on. I made it just off the highway before it started over heating (stupid traffic). Should be back on the road Wednesday when the part arrives at the stealership. Anyone have some insight on the failure and if I should be concerned any further than the idler pulley? Let's hold off on talk about the water pump, there's enough information out there on THAT.

I've not heard of a roller siezing before, usually they rattle and move around on their spindle (as mine did).
You can bet that the other idle roller and the tensioning roller will be candidates for replacing too if one has already failed.
Just be carefull when you torque up the bolts - DONT use the torque specs in Dempsy's 101 Projects for your Boxster book, they are wrong. I know from hard experience .......

My idler pulley whined for 25000 km and gradually got worse. I used a hollow pipe and pressed it against each pulley bolt head until one was obviously the culprit. Then replaced it. Maybe you were just used to the noise??? I wonder what bent the bolt?

I had the AC idler seize on my Toyota without warning, of course the 36" mud tires may have covered up the sound:)

I forgot where, but there's a site you can order a new bearing for around 5 dollars and have the old ones pressed out and new ones pressed in.

I replaced the bearing in both mine for under $20.

I think I would've noticed a whine, this is my second Boxster and this one happens to be quieter. I'm not sure how the bolt bent, I'm thinking it was coming loose and this allowed the pulley to pivot and jam on the belt. I'm glad the bolt wasn't broken clean off! All things considered it's a a relatively cheap fix. I splurged on the OEM dealer part since the turnaround time was relatively quick.

Can anyone tell me what the torque is on the pulley?

6203-2RS Bearing 17x40x12 Sealed Ball Bearings:17mm

Idler shaft torque values.

Upper idler (M10 x 145mm bolt) = 65 Nm (48 ft-lb).

Lower idler (M8 x 55mm bolt) = 23 Nm (17 ft-lb).

Great link. Thanks!

Just one per pulley? Two fixed pulleys and the tensioner?

Yes and yes.

When my first idler went, I also tried the replacement bearing rout. Bought good quality SKF deep groove ball bearings and (with difficulty) pressed out the old units and installed the new ones. Looked OK on the bench, but 5,000km later (on the annual service) when I checked my belt and tensioners, one new bearing was very gritty & the other slightly rough - they wouldn't have lasted much longer. I replaced them both with genuine Porsche rollers.

So be careful, as you need a good press and be very accurate with your alignment when pressing in the new bearings!

Thanks guys, I appreciate it. Hopefully once I put this new pulley on I don't find any other issues because of the overheating.

Porsche quoted me $103 each for the two deflection rollers and $117 for the tensioner roller. Both of my DRs have slight play in them. May just do that for piece of mind and a new roller surface but new roller bearings for $25 is tempting to try. I pressed my own wheel bearings in.

Question. Is there an optimum tensioner position? After UD pulley, I had to experiment with a few belts and one fits great but the tensioner is very close to its fully retracted position. Also, belt brand? I'm finding with my WP swapped that some start up noise is just belt squawk like a scrunch sound for a minute until it warms up. A shot of WD makes it quiet for a few days then it's back.

When I installed my underdrive pulley (bought from Flat6), it came with Gates belt Micro-V AT #K060806. A bit of a tight fit if I remember correctly, but runs OK.

By the way, WD40 is not good for a belt - better to use a proper belt dressing lubricant which lasts much longer.

I never use belt dressing, in my experience it just collects dirt, and makes the belt run loud.

That's why I was thinking new belt or different brand. Napa is close to my shop and had the black belt dressing but it's like tar and sticky and actually made the belt more audible.

Price on new pulleys is about $70 each for oem supplier from Pelican. And AutoZone has these at 45 each. Has anybody use the Duralast from autozone before? Also the parts at autozone are the same part for upper and lower pulley, but I know they're separate part numbers at Porsche. I wonder about this.

WD40 is not good for a belt
 

WD40 is not good for anything....seen lots of fine antique firearms ruined because WD40 (Water Displacing) removed all the petroleum in the steel and they were stored in that consition....use a specific product like was recommended:cheers:

I have all the press equipment for removing and replacing bearings in the pulley.
A word of caution if you are using a lot of pressure - example a 20T press. Follow the standard Intelligent Machinist best practices otherwise you may crack the pulley. Despite all this I did crack one of mine ! Most mechanics would not have pre-cleaned the pulley carefully enough to notice the crack !
Do not try to just press out the old bearing. Soak it in penetrating fluid for a few days .Work the bearing slightly in/out and re-soak ,repeat. It may take days before the bearing eventually comes out with reasonable force. No beating with a hammer and drift !
Clean the inside of the pulley scrupulously . Freeze the replacement bearing . Warm up the pulley .I used a little 'bearing fit' as a lube when installing the new bearing.
Make sure it is fully seated .Work quickly because of the bearing fit! Make sure the bearing is 'square' in the pulley. Spin the pulley on the new bearing to check for run out. It is easy to distort the pulley if you are clumsy with an overpowering press.
Check that all the pulleys are aligned with a long straightedge. The a/c pulley on mine needed a shim.
But why do all this? Rock Auto has the Pulley for the price of a bearing !NAFYYY
RockAuto Parts Catalog
and

RockAuto Auto Parts

Steve, Do you have the torque spec for the tensioner bolt? Thanks, Chris

Lost mine with no warning. It didn't seize though. It just fell off. Was just pulling off the expressway and heard a load bang behind me. Didn't know what it was until I tried to make the turn onto the road and realized I had no power steering. Then I realized that the belt must have snapped.

After nursing it home, I checked out the belt and it was in one piece and had no mark on it. Took me a few minutes to figure out I was missing the pulley.

Side note: I found every piece of the pulley, but opted to get a new one anyway along with a new belt.

No slam intended
 

for all I have read about these UD pulleys, I will stick with factory :cheers:

upper idler failure
 

Hello guys,

i have a 2001 Boxster S with 204 000 km on it, last saturday night i was coming home, and when i took the highway exit i revmatched downshift in 4th gear, then same for 3rd gear, and then my gf and I clearly heard a KLOK KLOK! right in our back.

Having lost the power steering, i initially thought about a flat tire, but quickly stopped to realize that my tires were all fine and smoke was coming out of the engine bay.

I quickly got back in the car, where now i could see the battery light on, so at this moment i figured out that my Main belt snapped for sure.

I replaced this belt myself at 170 000km in 2017 as a preventive maintenance, but i cheaped out the idlers as everything seemed to be fine with them.....WROOONG!

So as soon as I realized that the belt was gone, i was around 2km from my home so i decided to stare at the coolant temp gauge and try to go back home prior to overheat or just run out of battery, which i managed to do.

Today i opened the cover to discover the damage, remove any dust/chunk/strip/wire of what could initially be called a belt. I even passed the vaccuum in every corner that I could reach. The only damage that i could see was that the upper idler was completely destroyed ... here are a few images

http://986forum.com/forums/uploads02...1591748894.jpg

http://986forum.com/forums/uploads02...1591749092.jpg

http://986forum.com/forums/uploads02...1591749196.jpg


http://986forum.com/forums/uploads02...1591749414.jpg

Surprisingly, the bearing of this idler was still super smooth and quiet (i verified it prior to unscrew its bolt from the engine).

So, for all you guys who are thinking about just replacing the bearings inside it, think twice. The steel part of the pulley is actually pretty weak for a Porsche part. One one of my above pictures, look inside how corroded it is, my lower roller also shows the same rust flowers in the interior corner.

My conclusion on my issue is the following:
-The idler roller itself started to break due to fatigue and rust, which ejected the strap off and got worse as the strap was probably pulling hard from other elements in rotation...

My solution:
I ordered directly at Porsche Dealer a new belt, new upper and lower idlers, and the roller of the tensioner, for a 577$ CAD tax in. I will be replacing all the parts in 1-2 days, I will keep you guys updates if there is another problem with my car or not.

Sorry for the long story, thanks for reading!

Wow, thanks for sharing that. I rebuilt all my idlers with new bearings, but those were in much better shape, and only 100k in the car. Maybe yours had been rebuilt too somewhere in the past and this one got a little crack due to pressing the new bearing in and just gave it up now. I heated up mines and cooled down the bearings when I installed them to minimize the chance of damaging the pulleys, because they are indeed made of very thin material.

I think that you are exactly right about the last detail that was missing to my investigation! Alot of people will not seat on the right surface to press the bearing in and/or out. And on the pictures we can clearly see that the breakage would be pretty similar if we would voluntarily seat on the outer ring and apply big force on the bearing insertion’s axis.

I also use the frozen bearing and slightly heated housings (because of aluminum parts) for the wheel bearings jobs to reduce the interference fit and make pressing work a charm! Thanks for your reply! Porsche should have my parts tomorrow!

Holy Toledo! I changed my belt yesterday. Actually yesterday. I checked the pulleys, but didn’t do new bearings. Should I, I just turned 100k? New water pump, (3rd) new alternator at 70k. Best of knowledge, no maintenance on rollers


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Idler pulley....
 

....while there are not a large number of these failures, enough of them have grenaded like this and left people stranded, and in a couple cases that I am aware of, destroyed the car with a belt fire that spread, that I feel you should replace all of them when you replace the serpentine belt.

Most of these cars are over twenty years old now. Stuff wears out. And stuff TIMES out.

When I bought mine, I had the serpentine belt and all of the idler pulleys replaced. The car is a 2004 and when I bought her in 2015, she only had 25,000 miles on her. The technician told me it was a good thing I told them to R&R the pulleys, because one of them was in bad shape upon inspection, even though there were zero symptoms of any trouble brewing.

I upgraded to the later, lighter pulleys with better bearings.

Idler Pulley Failure
 

My pulley failed at startup. It initially sounded like a hung starter (squealing). In the process of replacing it, I discovered the Overdrive Pulley on the Alternator was seized which may have led to the failure to begin with. It was the pulley just downstream of the alternator. I ended up replacing the alternator and pulley and added a new belt as well. My recommendation is if you have a sudden or catastrophic pulley failure, check out the Alternator Overdrive Pulley carefully (on manual transmission cars). If the the ODP clutch is seized, it can put a lot of stress on the whole belt drive train.

Where did you source? Have a parts list, I’m doing it


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So, I’m in the fence before I button everything up. 100k and I think I would be comfortable replacing the idler pulleys or at least the bearings, just need to build a parts list. The kits out there are 300 dollars. Advice?


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My car is fixed
 

Hello guys,

just to follow up on my repair, Porsche received my parts friday morning so after work i was able to reassemble my brand new upper, lower and tensionner rollers successfully along with the new belt. My car seems to be 100% back to normal, tested today with some savage 3rd and 4th gear highway entries :P

here is the video of the first startup after repair where you can easily see the new parts and hear the pure Porsche powerful sound :)
https://youtu.be/S2PQG5oh9f4

I think that it is not wrong to replace the bearings but the roller themselves require serious inspection and you never know what previous owners could have done like i found out on my car!!! If you decide to replace the bearings, make sure that you never apply strain on the outer ring of the roller while removing or pressing the bearings in them. And always put the new bearings in the freezer prior to insertion.

In the end, they are not too expensive parts even at the dealer and they are so important to be right as this belt operates absolutely everything crucial. I bought peace of mind. It was also a very pleasant job to perform in the end.

http://986forum.com/forums/uploads02...1592113956.jpg

Remove each pulley. From each pulley remove the plastic ring that protects the bearings. Using brake cleaner... carb cleaner... spray out the bearings... clean them up... apply dabs of grease to the cleaned bearings... reinstall plastic ring... reinstall pulleys... enjoy.

If noise remains identify the errant pulley... replace the bearings... you're good to go and you save $190.

:cheers: