cbzzoom

My serpentine has been squealing a bit at startup for a while, so I read Edgy's thread

https://rennlist.com/forums/997-foru...failure-2.html

and it looked easy enough so I figured I'd swap it. Well, I get in there and crank on the 24 mm hex head and ... it just spins. Frick. My understanding is it shouldn't spin, but rather when you push on the wrench it should just move the pulley.

So, anyone know why it's just spinning and how to fix it !?

Edgy01

So you're saying that the tensioner pulley wheel simply rotates easily with the use of the 24mm hex wrench? It doesn't exert any tension upon the serpentine belt?

Of course the WHEEL portion of it should spin, but the entire assembly should move as you release the tension from the belt.

As I have come to understand these things (along with the two come along wheels--all this applies to 997.1 only) are considered expendable 'wear items' by Porsche. It is becoming commonplace to replace the three wheels (two come-alongs and the tensioner) when the belt is replaced.

Give us perhaps a little more insight into what you're experiencing.

cbzzoom

I put the 24 mm wrench on the hex head bolt on the tensioner pulley wheel. I apply torque clockwise, and the hex head bolt just spins on the wheel, it doesn't move the wheel to reduce the tension.

I found there is a 15 mm bolt in the back that secures the thing -

https://rennlist.com/forums/997-foru...at-urgent.html

maybe that's too loose? But I'm not sure how to get access to that.

Edgy01

If the 15mm bolt (on the rear) is loose you may have to make a special tool to hold that one still as you attempt to release tension with the 24mm. As you have discovered, the access is very narrow. You would really need a thin oil line wrench (or grind a regular 15mm to half its thickness).

I believe that 15mm head is manufactured into the material and is supposed to remain fixed as you apply torque with the 24mm wrench. At any rate, that tensioner wheel is shot and will have to be replaced. Under warranty? If not, it takes a bit of work but you need to get that thing off.

Sometimes it pays to order the part so that you can see what you're dealing with. They're not that expensive and yours sounds like it needs to be replaced.

cbzzoom

.. bumping my old thread.

Belt has been squealing as it's gotten cold recently. I got sick of the squeal that would bug me for the first 5 minutes of every drive and went out to take care of this.

Now, I still start from the same problem I posted before, my dang tensioner pulley wouldn't de-tension, I'd just crank on the 24mm hex and it would spin instead of moving the thing. I thought I'd try just tightening it. I have a super thin 15mm "cone wrench" for bicycle work that got into the back of the pulley handily, and then I just cranked the front and back together. There's no space to grab that 15mm wrench on the back, but with some really serious grunting, I got it tight. (note to self : don't brace yourself on the car's body panels, they're thin!)

So, then I was able to crank the tensioner pulley and get the old belt off pretty easily.

I thread the new belt on up to the last pulley, crank on the tension pulley and try to slip it over the idler - it won't go on. No way. Man it's hard work cranking on the tensioner pulley too, who said this was a 10 minute job?

I take the belt off and try to stretch it and loosen it up a bit and try again. Not even close.

I take the belt inside and heat it up a bit by putting it in front of a space heater for a while. Try to stretch it on again. Hmmm pretty close this time.

I just need a little more, so I tie a piece of cord around the belt where I need to pull it onto the last idler pulley. I crank the pulley again, pull the cord - phew it's on.

My understanding the tension on the 997.1 is non-adjustable, it's just mechanical from a spring, so it can't be that my tension is "set wrong" , but it certainly seemed like too much.

I did notice some of the grooved pulleys had some little pebbles or bits of road junk stunk in the grooves, so I cleaned them out with a tooth brush.

997_rich

You made me a bit nervous when you we speaking about "stretching the belt"- that belt shouldn't stretch. It may stretch slightly over time, but stretch like a guitar string, not like a rubber band. The tensioner arm does the stretching and tensioning, not the belt.

It sounds like you don't have good mechanical advantage over the tensioner assembly. Usually when I do this job I might put a slim pipe over the end of the wrench so you can easily crank the tensioner arm back with one hand. You should be able to crank the tensioner arm all the way back to the mechanical stop with the wrench and hold it there with one hand. Don't bang it against the mechanical stop hard, just crank it all the way back and hold it there. Then the belt should go on easily.

there's also the possibility that your tensioner is shot. I haven't looked in a while but i think this car (like most german cars) has a damper on the tension arm. The damper can fail and kinda bind a bit. That might be the source of your problem. This can also cause less than optimal force on the belt because the spring can't move the arm out as easily as it should.

cbzzoom

Yeah, the big problem is the tensioner bolt was loose, so when I would crank on it, the pulley would move, but the bolt would also slip a bit. So I would get the wrench all the way down to where it was running into some hoses and the pulley wouldn't have moved enough. I think that bolt is supposed to have lock-tite on it.

I'm gonna have to take the car in and get the whole tensioner pulley / etc. replaced and installed right.

LlBr

I'm late to the party but maybe this 997.1 item will help a little. Good luck.

gpjli2

I have just crossed this off my DIY list.

997_rich

It's really no big deal. seriously, totally DIY. take a pic of the belt with a digital camera if you're worried about it. other than that it's just pulling back on the tensioner, take off the old belt, put most of the new belt in place, pull back the tensioner, put the last bit of the belt on.

pulling back on the tensioner is the toughest part and it really only takes one wrench. watch a youtube video on it or something.

Remember this is just the serpentine belt. It's not the timing belt/chain.

cbzzoom

I think if the tensioner moves fine for you it should be pretty straightforward.

If the bolt slips, take it to a shop IMO. (that's what I'm doing next time)

Like all work on cars, it's pretty easy as long as everything goes the way it's supposed to (which it never seems to, there's always a rusted bolt or an over-tightened bolt or etc...).

Kahdmus

I am having the exact same problem . With the tensioner bolt on my 996. Is it the same?

USMC_DS1

Check the PET for your 996 but it's likely very similar if not the same. I had this issue on my 997.1. You need to get a short 15mm wrench for the bolt head in back(it's a tight space back there) and then use the 24mm wrench to tighten the front tensioner nut against it.

7500rpm

The engine must be stone cold before you attempt to rotate that tensioner, its in the instructions. I learned it after facing the same problem but the tensioner rotated once the engine cooled completely. Hope this help.

Kahdmus

This was exactly correct. Standard 15mm wrench, quick turn anti-clockwise and all was well! Thanks so much!