bureau13

So after much trial and tribulation, I finally got the damn AC compressor bolted back up to the chassis (no belt yet) and went for a drive. Everything seemed great, but on the way home, I got a belt tension warning. I find these to be extremely stressful lol...however my temps were rock steady and I was close to home, so I continued and parked it in the driveway (not sure how risky that is, but...oh well). Nothing looked amiss under the hood, no water or anything. Clearly the belt was not broken, so if the water pump didn't seize, I'm guessing it was either on the edge, or the warning system falsed. When it cools down, I guess I'll pull the cover and take a look.

bureau13

Hmmm, I'm reading that the S3 motors need belt tension set to the high end of the range on the Kempf tool. Not sure why I didn't know that when I first go the car, but I'm pretty sure I set it in the middle (it was low when I first got it, I'm assuming it was never readjusted after initial belt stretch).

GregBBRD

The belt tensioning light is one of the best things Porsche did to "protect" these engines with their long rubber belt from damage.

Very reliable, very predicable, and very accurate.

If the light comes on when you are de-accelerating and can be reset by shutting the car off and then back on, the belt tension is under 3.0. (I have no idea how that translates to a Kempf tool.....I do not own one.)

If it doesn't reset, consider a tow truck.

Of course, you can just eliminate the belt light, like Porken's tensioner does.

He's apparently a proponent of the theory that "ignorance is bliss".

bureau13

After peering down through the cam cover "ports" while cranking the engine over by hand, and noting that everything seems "normal" (i.e. the belt is still intact and feels the same as it usually does) and remembering how I had set tension before, I tightened it up a bit (just a few cranks of a wrench, maybe one turn total) and started it up again. The light was off, but came on again after 3-4 minutes. My understanding was that it would always wait that 3-4 periods of warm-up time, have I misinterpreted that?

A few FWIW observations, that may not be relevant: I have at most 0.5" of travel left on that tensioner bolt. Is it normal to have that little travel but still be at the loose end of the spectrum, in terms of tension?

When I got the car, the light would always come on after the warm-up time, because the wire was not connected. I set tension (it had been loose) and connected the light, and it has not come on since then. I know the belt and water pump were done in 2012 and it has had few miles since then, but I don't know what kind of pump nor who did the work. My plan was to do that job some time this calendar year.

I am actually considering the Porken tensioner (not trying to start one of THOSE threads ) but one thing I am NOT considering is assuming it's a warning circuit problem and grounding the connector. It doesn't really stay attached to the cam cover very well, but still....if the stock tensioner is present, I want the warning light to work...it's worked with no falsing up until now.

I have no idea if there is actually still oil in the tensioner or not. It wouldn't shock me if there were not...but like I said, it hasn't indicated a warning until now.

OH, yeah...I don't know if I was decelerating or not when it first came on...but I wasn't pushing the car hard at all...just cruising around town. After my little test, it came back on after the warm-up period at idle, although I was reving it a bit.

zekgb

Take the right side cover off and check the tension immediately, don't just tighten as an overtightened belt can lead to premature wear to the gears and water pump. If tension is ok then inspect the warning circuit, there are several possible failure points for the circuit which will cause false alarms. Check the warning circuit for continuity to ground by unplugging the warning circuit wire at the center cover and attaching your multimeter to the plug end with an alligator clip. Continue to check for continuity while manipulating the spade connector for the center cover plug to test for intermittent connectivity. If loose at the spade end you will need to either re-crimp the female connector on the plug wire and/or bend the spade end of the connector so that it doesn't contact the center cover. You should also check the copper strap to make sure it hasn't broken (even after it breaks it may have enough contact to work most of the time.) If it has you can't really do anything about it until the next time you change the belt as the tensioner needs to be removed to change it out.

bureau13

Yeah, I only tried slightly tweaking tension due to my recollection of having likely set it lower than I should have from the start. You're right though...I need to actually check it, so I know for a fact where I stand. Tomorrow was supposed to be Expansion Valve and Receiver/Drier Day, but now I guess priorities change....it's Check Tension/Tension Warning Circuit Day.

Randy V

@ GB

davek9

OP, if you keep adjusting the T-Belt by stabbing at it, and not knowing things like oil levels and or ckecking and rechecking your work.
The AC won't matter, as it won't work un less the engine is running and it won't w/ bent valves.or worse.

bureau13

Of course... Did you read what I wrote? I explained why I tried the single tweak, and stated that today has become check timing belt tension day. I'm not driving it out starting it again until I figure out what is going on with the belt, believe me! I have a fairly healthy paranoia about timing belt tension warnings...

bureau13

OK, false alarm. Literally...I seem to have pulled the sensor wire off of the tab on the tensioner somehow. That little button connector thing that plugs into the cam cover hole doesn't really snap in for me, it just sits there...I suspect I loosened it by accident while messing around with the compressor, it's wire connection, etc. Btw when I checked tension, it was a little too high...so even when you think you can justify a little tweak without measuring...it's probably not that great an idea. Lesson reinforced lol...I haven't driven it yet, but I idled it for five minutes, gave it some revs...no light. Tension set to the high-middle of the Kempf tool window. Back to AC work

Randy V

A classic case of timbephobia!

dr bob

I mentioned recently in a different thread that the differences between mid-window ans high-window Kemp tool readings is about one flat on the adjusting bolt. That's 1/6 of a turn on the bolt. A full turn is more than "a little tight", and risks breaking the nose off the driver's side cam. I know you've done this already so no lesson for you now, but others reading along at home might need the info.

Back to AC projects?

FredR

During 16 years of 928 ownership I have had two belt alarms- the alarm warning came on, I accepted the warning and on both occasions the light went out. If there was an true alarm condition would the warnating not stay on or repeat itself?

Had the alarm stayed I would have abandoned ship immediately- is this a false logic? Needless to say on both occasions the tension was checked and nothing found. In such circumstance the main agents would tweak the tensioner 1 flat and leave it at that.

Personally, I would like to be assured that the tensioner alarm system is in fact working-is there a practical way to test this? Not too keen to try slackening the belt off to see if the alarm comes on. I check the tension every 6 months as a matter of course [with No1 at TDC].

Rgds

Fred

bureau13

Good info, Dr. Bob...I was wondering how course that adjustment was.

Fred, when you say you accepted the warning and the light went out, you mean the big red "!", right? Did the "belt tension" indicator disappear also? I've only seen the indicator when my warning circuit was disconnected, so I don't know if a transient condition will allow the indicator to go out on it's own or not. It's a good question, since I haven't seen that scenario myself.

PorKen

You should be very happy!

But you aren't, sadly...going so far as to resorting to having my posts deleted by IB?



EG. here - see quoted post, actual post removed - one of two posts deleted due to "Non sponsor advertising"?


The text of the second deleted post, below. Anyone who has had to deal with Greg's 'impartiality' knows what I'm talking about.

Greg is a good guy...especially if you are a paying customer...but that does not change his MO, whether he knows it or not.

1) He decides he does not like something that did not come from his own praxis

2) He "tests" that something and finds it faulty, often due to not following the directions

3) Continually refers to his "testing", even if others are successful in using the product