[s-cars] Subject: Serp belt woes

[Tom Green]

Aaron,

Now that you have snow It's probably not a good time to work on the a/ 
c.  :-)  The system does not engage below about 46F IIRC.  When the
temperature warms up, you can engage the clutch with the ignition  
switch on.   Run the temp selection to low and select auto and you  
will hear
the clutch engage.  You are probably within 1 or 2 degrees of optimum  
performance with a 40F duct temperature.   Any lower and condensation
will freeze on the coil.   I don't know of anyone who has said their  
compressor failed after they got the turbine sound, just that it is  
annoying as hell, and pedestrians scatter thinking a F-15 is making a  
low pass.  :-)

I have no doubt that Blau provided the correct belt.  A lot of this  
griping comes from those buying the cheapest internet deals and  
expecting the
highest quality parts.  You have be an astute buyer to play that game  
since the traditional German part suppliers really feel the pinch  
from the
Chinese parts hitting the market as the euro soars to new highs.   
Some North American manufacturers are competitive now.  At least Blau  
knows
Audis and you don't have to double check every part.  They were one  
of the earliest dealer alternatives in the US and so the business  
model is
lower price for German quality.  I don't think they have totally  
accepted that those German suppliers are sourcing from suppliers  
first in the former Bloc countries, and now China.  It has really  
turned into buyer beware, but also realize that a miniscule number of  
complaints on the internet is magnified by user sites like this where  
shared experience is the reason for its existence, so you want the  
whole story of how they handled the
complaint.  Some of the internet sites that cut prices don't have any  
customer service telephones or anyone to verify the part is correct  
and won't accept a return unless it's defective.  This isn't about  
defending Blau, but about accepting that rock bottom price isn't  
always what you want.  Sometimes you need accuracy and timely  
delivery or help finding the correct part, which is why the dealer is  
still a source, why some of the popular suppliers are successful, and  
why you can't have one supplier that is best for everything.

If you have your old tensioner or need a rebuild of the bearing I  
still have most of the rivets for the split pulley that I sourced  
from McMaster-Carr.
They come in packages of 100 and the pulley uses 3.  :-)  I have two  
in use with replaced bearings.  If the spring portion shows any wear  
or is badly corroded, I would not reuse.

Tom


On Jan 17, 2008, at 11:19 PM, Aaron Ryba wrote:

> Tom,
>
> Yeah, we finally got some snow here last night, some more on the  
> way  too. And the s-bitch hasn't had it's annual playtime in an  
> empty snow-covered parking lot.
>
> The brand of belt I have is whatever Blau includes in it's serp  
> belt kit. I purchased it before realizing Blau has a reputation for  
> not so good part sources. At least the tensioner was an OE part.  
> Not sure on the belt, would have to do some research.  I at least  
> have a feeling the being Blau they do match up the correct belt  
> length. When installed new last year the cracking noise from the  
> old tensioner did go away. Now as I am thinking, the noise was  
> possibly due to a worn out belt from running the AC rather than a  
> bad tensioner. I could have saved myself $195 with just the new  
> belt and a rebuild with new bearing. Oh, well, what would the S6 be  
> without gobbling up all my scrap pennies?
>
> Due to the weather I still haven't had a chance to check for  
> turning resistance on the other pulleys. How would one have the AC  
> clutch engaged while the engine is off? I was wondering how to do  
> that earlier today. Do you just run the engine sans serp belt with  
> the AC button on and be super careful while your mits are moving  
> around down there checking for the compressor resistance? Please  
> tell me there is another way. Haven't bothered yet to check the AC  
> head unit for codes as there is most likely a code there now as I  
> have run the engine without the belt on. When topping off with some  
> 134a this summer I checked for codes and there were none at that  
> time. Thanks for the offer of your old compressor. I thinks I need  
> to do some research and diagnostics on the one on my car before I  
> take delivery of yet another part that will sit on my shelf or the  
> wife will kill me. I might take you up on it in the future if  
> needed. With the recharge/top off the performance
>  is much improved. Not the best at only about 40 degrees at the  
> vent but good enough compared to the practically no change in temp  
> before. The jet engine noise didn't happen though until this fill- 
> up. I haven't done my homework on a failing compressor though so  
> I'm not sure how long it will hold up.
>
> After I check the other pulleys I'll post my findings.
>
> Thanks,
> Aaron Ryba
> 95 S6 (sleeping)
>
> ----- Original Message ----
> From: Tom Green <trgreen at comcast.net>
> To: Aaron Ryba <aaronryba at yahoo.com>
> Cc: s-car-list <s-car-list at audifans.com>
> Sent: Thursday, January 17, 2008 7:21:52 PM
> Subject: Re: Subject: [s-cars] Serp belt woes
>
>
> Aaron,
>
> You must be a slow typist or a whiz at belt replacement.  :-)
> Especially doing it in the cold--a little snow in upper SC last
> night?  The old practice of carrying a spare belt for emergencies is
> not much help with this car if fails on the typical dark rainy night
> in the mountains with no shelter available.  It is challenging enough
> in the garage and just remembering how it is routed is a feat for me.
>
> You did not mention the brand of belt you were using or where you
> purchased it.   The local flaps can match up a 6 rib belt by the old
> belt length or their parts catalog but the length may not be exact.
> They seem to think a few mm doesn't matter since they all use a
> tensioning system to take up the slack, usually longer since shorter
> may be too difficult to install.  Much in the same manner they will
> sell you spark plugs because they are physically the same size but
> may not be a good choice for your engine.  When buying online, I buy
> two to spread out the shipping cost or get the minimum order for free
> shipping, and have a spare at home.  There are 3 S6's on my block
> that might need one.
>
> I changed a compressor because of the roar and because I thought it
> did not cool as well compared to other S6's.  The new one cools the
> same and makes as much noise, i.e., no change except to lighten my
> wallet considerably, so I would evaluate the a/c on performance.  I
> think your belt problem lies elsewhere if you can turn the compressor
> by hand with the clutch engaged (no belt).  It does take some engine
> power to operate the compressor.  I put the shipping plugs in the old
> compressor and its  been on the shelf for a year if you want it.
>
> I would clean the tensioner spring portion as much as possible and
> lubricate with a high quality grease.  Those I have seen failed are
> badly corroded and fail catastrophically, throwing belt parts
> everywhere.  Since the pulley spins freely by hand I also think the
> tensioner is fine, and the noise you hear is coming from elsewhere,
> just transmitted to the tensioner area.
>
> Check the fan clutch to ensure the fan freewheels when it is cool and
> does not wobble excessively on the bearing in the support.
>
>
> On Jan 16, 2008, at 11:01 PM, Aaron Ryba wrote:
>
>> Thanks everybody for the input.
>>
>> When I ran the car without the tensioner I mean I removed it and
>> the serp belt so no accessories were running, only the timing belt.
>> I wanted to make sure it wasn't the TB tensioner/bearing which it
>> wasn't.  What is weird is that I also ran the engine without the TB
>> cover but WITH the tensioner and belt and the same noise persisted.
>> The noise which I thought was the sound of the tensioner roller
>> rubbing against the TB cover (wear on the cover to prove it)
>> persisted without the cover. I didn't put a stethoscope on anything
>> but I am fairly certain the rumbling noise is coming from the
>> tensioner bearing and not the other pulleys. I'll try the DIY
>> stethoscope with some rubber tubing this weekend. I haven't yet
>> tried to freely spin the other pulleys, I know the steering pump is
>> spins well, it could be the AC compressor. I'll have to look when
>> its not snowing outside. I would describe the noisy compressor when
>> running to be like a "jet
>> engine or turbine sound," so it seems like it is failing like others
>> typically do.
>>
>> With the serp tensioner out of the car the bearing roller turns
>> just fine and without noise or problem and there isn't any play in
>> it. It will turn about 4 or five times with the spin of my hand.
>> The reason why I think it is a belt problem is because the
>> tensioner seems to be fine. The spring is still very firm as
>> evidence by how much force is needed to lock it into place for
>> removal. From reading in older posts it seems like when tensioners
>> fail it is the bearing and not the spring. I assume a sticking
>> bearing will improperly load the spring and hence the cracking
>> noise.  I agree that even with a stretched belt, the slack would be
>> taken up with the tensioner however the cracking noise from the
>> spring in the tensioner only happens when under load from idle when
>> doing a three point turn or pulling away from a standstill so
>> perhaps it is only at these moments of low RPM when the slack in
>> the "stretched" belt is enough to overcome the tensioner spring. It
>>  seems like when the RPM is raised there is more tension on the
>> belt and hence the cracking noise goes away. I don't know if that
>> even makes sense. Oh well.
>>
>> The secondary scraping rumbling noise (i assume from the bearing
>> itself or from rubbing against the TB cover) happens all the time
>> and is loudest around 2k rpm. Not a very loud noise but noticeable
>> even from inside the car. These noises all seemed to gradually get
>> worse over time,  and the fact that I started to use the AC over
>> the summer for the first time since I replaced the tensioner and
>> belt makes be think it is the AC which ruined the belt. Due to the
>> AC compressor not being totally seized but just harder to rotate
>> maybe it is possible that put the undo stress on the belt gradually
>> which would otherwise have heated up and shredded had the
>> compressor seized up instantaneously.
>>
>> I guess the cheapest solution right now is to throw on a new belt
>> to the tune of about $25 and keep my fingers crossed. If that does
>> it I will keep the AC off till I can fix that. The non-AC spec belt
>> is a good idea, I thought of that as well but being in SC here for
>> the summer I'd rather pay for a new belt every year than go without
>> the AC, granted the compressor lasts much longer that is!
>>
>> All this typing and I could have already replace the belt by now.
>>
>> Aaron Ryba
>> noisy 95 S6
>>
>> ----- Original Message ----
>> From: Tom Winter <tom at freeskier.com>
>> To: s-car-list at audifans.com; aaronryba at yahoo.com
>> Sent: Wednesday, January 16, 2008 10:00:30 PM
>> Subject: Subject: [s-cars] Serp belt woes
>>
>>
>> Aaron - I'm no expert, but I'd expect the tensioner to last longer
>> than
>> that. I did have some noise issues from a serp belt, not a rattling,
>>  but it
>> was making noise (and then broke, solving the noise problem! LOL!).
>>
>> Perhaps you'll get lucky on this one and it will be just the belt.
>  You
>>  said
>> you ran the car without the tensioner - I'm not sure how you did
>> this -
>>  and
>> there was no noise under these conditions. But I'm wondering if the
>>  other
>> pulleys in the system aren't worth taking a close look at. Perhaps
>> when
>>  the
>> belt is under tension, they are the source of the problem. Just a
>>  thought. .
>> .
>>
>> Good luck.
>>
>> Tom
>> '95 S6 Avant, waiting on parts
>>
>>
>>
>>
>>
>>
>>
>>
>>
>   
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