machina

So what is the tension spec for the belt and where do you check it? I happen to have a german tension gauge in my kit and wanted to check mine.

gota911

Dan, thanks for the update. This is very interesting topic.

When they replaced your the water pump at 9K mikes, maybe the tech set too much tension on the tensioning pulley, thus causing the recent issue. The water pump failure "could" have been an isolated incident, not related to too much tension on the pulley, or the water pump failure "could" have been a result of too much tension on the pulley. Obviously, relative to the water pump failure, it is impossible to determine which was the cause and which was the symptom.

pbarch1

My belt has squealed from the first day. It only does it from a stop, and only instantaneously when I accelerate. I've had it looked at twice, and they replaced the belt once. After reading this thread I'm wondering if there isn't something else going on that I need to have addressed. Very interesting,

Thanks for the post Dan….

uzj100

My water pump was just starting to fail and I had no issues with the pulleys. It was Dan's experience which prompted me to re-check my coolant level and led to the discovery of the pending WP failure. (I've never had below min coolant level) When we returned to his house--just after he shredded his belt--we checked my coolant level and noticed it was down.

As Dan commented earlier, we ran into another club member at the dealership who had his car in for the sway bar linkage issue. (My front sway bar links will be replaced tomorrow).We then checked his pulleys and noticed he had some grooves developing on them.

OCBen

Sounds like a loose belt. When a belt is not tensioned sufficiently it will squeal whenever the engine is revved, an indication that there is insufficient normal load on the pulleys to generate the needed friction to turn them. Generally the squealing comes from the crank pulley, the driver pulley in this case.

In my case, I have a squeak that is heard on each cycle of the serpentine belt. It occurs approximately at a frequency of 2Hz, or 2 cycles per second, at idle.

Edgy01

I asked the mechanic about the tensioner and whether there is some ideal setting for them. He indicated that the tension is fixed. It is governed by a spring within an arm that is attached to the tensioner pulley. (Not hydraulic nor adjustable).

The 997.2 engines appear to have a fully separate tensioner which may provide Porsche with a range of tension settings, but this is purely speculation on my part right now.

As always, I will continue to research this. I recommend for even the armchair mechanics to go out to your engines and feel for grooves on that top idler pulley. You may discover something.

jw1977

Do you have any idea what this would've cost to replace if you were out of warranty?

Edgy01

I can't imagine the little pulleys being that expensive,--being plastic. Three of those. The belt at Suncoast (and probably Sunset Porsche) is $28.38

The real question is the troubleshooting cost.

They also have completely flushed the coolant system (5 gallons at $23 a gallon) and replaced all of it, along with a new coolant cap ($15).

OCBen

Those pulleys are not made out of just mere plastic; they look more like composite material. And being made of composites I'm sure they're not cheap. They're likely more expensive than had they been made of aluminum alloy material.

ADias

They are probably Delrin.

OCBen

Maybe not. Delrin's a thermoplastic and begins to lose strength around 200 F. I suspect it's probably a fiber reinforced thermoset material that's better suited to high temp environments. I could be wrong. But I suspect they're not cheap.

Edgy01

If there's a Porsche Part Nr. on it it will be expensive. I will try to get the run down on the prices on Thursday when I pick up the car.

(At least I'm also getting two new PSE sport mufflers and two new exhaust thingys (the shiny things) too, tomorrow!)--Separate issue. (Fractured welds on these things' mounting points).

ericthepilot

Hello Edgy

Sounds just like airplane parts. The GE light bulb at Sears costs 29cts. The same FAA approved bulb w the matching part numbers +1 suddenly is $4.89. And where is the difference ? Put them all in the same bag and you could never tell.
Sorry to hear about your belt issues, hope that your excellent reporting on this event will help us all around to better grasp what is going on behind our backs.
Thank you, and have a great summer drive this year

theporscheguy

Also take a look at the tensioner which can sometimes be the culprit. Another brand I used to own would at first misalign the belt and then start cutting parts off until the belt was gone.

BostonDuce

No offense to your mechanic, but WD40 eats rubber or it's synthetic derivatives.

It shouldn't be allowed anywhere near belt drives and their pulleys.

BD