Nexus-6

(cross posted at Renntech as well)

Hi folks -

In replacing the serpentine belt on my new-to-me '05 C2S, I noted that the routing pulleys and tensioner pulley were worn and grooved. Having read about this happening to others, I purchased replacements for all 3 and sure enough, the new ones are 100% flat across the shoulder, no grooves.

The two passive, routing pulleys were easy breezy to swap out, but I'm having a heck of a time with the tensioner pulley. As you know, clockwise compresses the spring for belt removal. Counter-clockwise swings the roller up towards the water pump pulley (and, sadly, in my case...right into it after a slip which has resulted in the old pulley cracking in several spots. So, what began as a simple replacement has turned into a "must do" as I won't be able to refit the belt until I replace the tensioner pulley).

I'm having heck of a time getting the bolt loose on the back of the tensioner roller. I'm doing it correctly I believe (applying force counter-clockwise to both the 24mm nut on the front of the roller, as well as to the 15mm bolt on the back of the roller holding the it together).

I'm using a breaker bar on the 24mm nut, but I'm only able to sneak an open end onto the nut in back - I'm unable to get enough leverage it seems to break it loose. Looking at the new bits shows me that they have red loctite (or their equivalent) on the rear bolt.

So, short of somehow doing this wrong (I've checked the new pulley and the bolts are not reverse threaded) - does anyone have any practical tips here? If I could somehow get a cheater bar/pipe on the open end in back, it would help, but I'm putting gorrila twist on the thing and it's just not coming loose. I considered using my impact wrench (as gently as possible) to jar the front 24mm loose, but there isn't enough room to do so without swivels.

Any ideas at this point would be greatly appreciated.

Sweeper

any possible way to heat (MAP gas torch (MAX) only) around where threads go into the blocK. This will soften the lock tite . Please don't use cheater bar on the wrench.

Good luck

Edgy01

Sweeper is on the right track. When mine was serviced even my factory trained mech. had a heck of a time with that puppy,--and he was replacing it with a new one! Heat is the solution. I wish you luck. I hope you saw my past posting on this.

Apparently, some of these cars wear out the idler pulleys as well as the tensioner pulley. As the tension is governed by a fixed spring inside the tensioner pulley I don't get it,--why is the tension putting such tension on the serpentine that it causes the wear on all the pulleys? It has to be one of the following:

(1) improper tension of tensioner
(2) a dragging accessory
(3) misalignment of something (an accessory)

There is something underlying here, but we don't know yet what it is.

I have noticed that the 997.2 engines have done away with that design entirely. The two come-along pulleys are gone, and the tension placed upon the 'tensioner pulley' is provided by a hydraulic design separate from the pulley.

Other discussion:

https://rennlist.com/forums/997-foru...t-failure.html

Nexus-6

Thanks for the tips guys - after much trouble (impact wrench at a relatively low 70psi did no good for what it's worth), I was able to encourage the bugger out another way.

What I ended up doing was this - removed the water pump pulley, and with the space then created, I was able to sneak a 15mm open end back there squared up properly with no angle or deflection. The issue of course was that there was precious little room for proper purchase on the wrench to counter with appropriate torque. The solution was to compress the idle tensioner a bit to get the angle on the rear nut correct, slip the 15mm into place and, here's the key, using a portion of the engine block extending out from below the water pump, I was able to wedge gently (with a shop towel to cushion the contact) the 15mm open end against as leverage. I then released the tensioner slowly back up which wedged the 15mm tightly. The engine provided the required counter force back there against the 15mm so that I could loosen the 24mm up front. Not without a verbal coaxing of course, but come out it did. I hesitated initially the evening before when I had this idear, but with adequate cushioning there was no issue with marring or damage.

Of course, once the tensioner was out, the reassembly job went quickly - maybe 15 minutes to get her back to good. In my case, all 3 pulleys had the same grooves worn as Dan's (and one of them had a bearing that was chirping rather badly to boot). The real reason I began this project was due to low alternator output after I brought the car home. I was seeing a peak of 12.5ish while driving and at idle, not high 13, low 14 as I'd expect.

In my case, there was a faulty alternator cable that was the culprit - but once replaced, my output was only at 13.3....better, but still not where it should be.

Replacing the 2 idler pulleys and the tensioner pulley, along with a new belt, did the trick. Back up to 13.9 under normal conditions.

My car has more miles than most - 56,000. No doubt this is why it was severe in my case, but I expect others have this issue and simply don't know it as it's not something we routinely check.

The only thing I didn't have handy was proper torque specs for the pulleys when reinstalling the new, fresh units. I defaulted to a 996 spec I found of 33ftlb, and that feels about right based on how they came off. Of course, if anyone has the proper values for the idlers, tensioner and the water pump (with the 3 retaining torx heads) for our 997s I'd love to see them.

Thanks again for the tips and if anyone in the near or distant future stumbles into this thread for the same reason, send me a PM and I can take pictures or give advice over the phone - always happy to help.

Cheers!

Edgy01

Would future removal of that tensioner pulley be easier with a custom tool, e.g., a 15mm open-ended wrench that was ground down to about half thickness so that it can get in behind the pulley as it is mounted?

Here's that pulley, from the backside,--this fastener is no doubt the 15mm one you were dealing with.

P.S. I picked up a Craftsman 24mm combination wrench which is now dedicated to the Carrera tool kit for use with the space serpentine belt--roadside repair kit.

Nexus-6

Dan,

That's the "bugger" of the entire process - that 15mm right there in your picture.

NOTE : I mentioned above that it was the water pump pulley but I was mistaken. It's the power steering pulley (silver) that I removed to make room.

The issue wasn't as much clearance as grip (or rather, a lack thereof). I was able to get the 15mm open end on the nut without removing the power steering pulley (flip it around to align with the nut orientation), however, there was simply no place to grasp it with enough counter torque to do any good. As soon as you began to twist the 24mm with any real grunt, it was nigh impossible to counter on the 15mm with just finger strength.

I am wondering if you can do me a favor - when you have a moment, can you take a few pictures of your belt alignment on your new pulleys? My old pulleys looked PRECISELY like your old ones did with almost perfect grooves worn in on either side...in fact, they were so perfect that it wasn't until your post on this subject (thanks much for that, BTW) that it looked as if that was intended design. But as we both know now, those pulleys are tabletop flat across the shoulder.

With 100 miles on the car, I've discovered that my new belt has aligned itself exactly flush with the rear/outter (towards the rear of the car) most edge of the pulley. The belt is lined up perfectly in each of the grooved pulleys, so nothing there is off contributing to this alignment on those two pulleys. Further, the belt is also perfectly centered on the top most idler pulley.

However, on my new tensioner pulley and the lower idler, the belt has walked perhaps 1mm to sit flush with the outer edge of the pulley. In this scenario, unlike the factory installed pulleys, the groove would develop over time and would produce only a lip along the forward/inner most edge (forward towards the front of the car).

I adjusted it to dead center on those pulleys again and will re-examine in another 50+ miles. But it would be useful to me if I could see if this is how it should sit on your new pulleys. It makes me wonder frankly if the factory installed pulleys had some alignment issues, perhaps resulting in the grooving we both experienced. In other words, perhaps the original pulleys install depth wasn't correct, or changed over time with wear/expansion and these new pulleys are "shimmed", if you will, in their length and flush with the edge is correct. It certainly isn't over the edge by any means - you can't even catch a fingernail on the belt if running up the side of the pulley - it is precisely flush with the edge. But it appears to have wanted to settle there flush with that outer edge on either pulley. It may be correct and I'm over analyzing now.

PS - I've been researching and reading here over the past 2 months as we're prone to do with new toys and I've found your posts to be wonderful and right up my alley. I'm a motorcycle nut and have documented many of the issues and work-arounds on my BMW K1200GT over the years in much the same way you've done here. I'm a sucker for Carrera Sport wheels as well, having them on my '07 Boxster S and in the process of securing a set for my C2S. Simply beautiful wheel on my opinion.

Edgy01

I'm glad that I was some help, in time for you. It appears that there are enough issues with the pulleys to justify a little extra time at inspecting them. My mechanic told me that it may become routine to replace all three of these with every belt change because of this wear.

I will be carrying a space serpentine belt and combination 24mm wrench in my on-board tool kit.

While I enjoy taking trips to out of the way areas (like in this picture), it appears that we will have to be able to help ourselves at times, which is in keeping with my some-35 + years of Porsche ownership.

Carrera Sports, ++ The widest OEM rims for the Carrera.

Nexus-6

Stunning picture there Dan - the more I see your car, the more I love that combo.

The scenery reminds me of the foothills just outside Boise, en route to Bogus Basin. Pretty, but the car takes the cake here.