Idler Pulley Failure

[CoBeerToad]

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.

[Pdwight]

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

[lucoche]

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










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!

[Homeoboxter]

Originally Posted by lucoche

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










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.

[lucoche]

Originally Posted by Homeoboxter

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!

[tonythetiger]

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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[10/10ths]

....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.

[BYprodriver]

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

[Tjkarp]

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.

[tonythetiger]

Originally Posted by BYprodriver

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

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


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[tonythetiger]

Originally Posted by tonythetiger

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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[lucoche]

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.

[Starter986]

Originally Posted by tonythetiger

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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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.