SergeSF

Hello all! New-ish member (been registered for about a year soaking up info).

Have an '09 997.2 C2S on PDK with ~61k on the clock. So far put about 3500 miles on it with virtually no issues since I picked it up last June.

Took the car out for a spirited drive recently and ever since have noticed a strange high pitched squeak/squeal at around 1500 rpm. Only happens during load, can't be recreated in neutral, will present itself regardless of gear. If I hold the revs when I hear it, I can maintain the sound.

My guess is something on the accessory side (idler, tensioner, or one of the accessories themselves). Before I start replacing various components, is there something that I should consider as the most likely culprit?

Anesthesia911

[QUOTE=SergeSF;16498849]Hello all! New-ish member (been registered for about a year soaking up info).

Have an '09 997.2 C2S on PDK with ~61k on the clock. So far put about 3500 miles on it with virtually no issues since I picked it up last June.

Took the car out for a spirited drive recently and ever since have noticed a strange high pitched squeak/squeal at around 1500 rpm. Only happens during load, can't be recreated in neutral, will present itself regardless of gear. If I hold the revs when I hear it, I can maintain the sound.

My guess is something on the accessory side (idler, tensioner, or one of the accessories themselves). Before I start replacing various components, is there something that I should consider as the most likely culprit?[/QUOTE

also consider your water pump if it still original ]
As your differential

jchapura

[Assuming your battery is not almost dead.] Warm up the car. Park it. Take off the serpentine belt. Feel the "action" of the components that spin, in your hand (you want smooth, greased bearing feeling).Take the car out for a (short) test ride to see if the symptom remains.
You might also measure your crankcase vacuum with a water manometer to see if you might be in the early stages of AOS failure. I've heard the failure sometimes has a "screeching"/sound associated with it.

ALEV8

Tensioner pulley /assembly bearing. Mine chirps as you let out the clutch in 1st gear. The entire tensioner assembly is a few hundred bucks.

SergeSF

I will look into both as they are original to the car. I think beyond the coolant expansion tank and valve cover gaskets, everything is original.

SergeSF

That's the next step I am taking. Short test drive w/o the water pump running should be fine I assume?

I'll check the vacuum, but from what I've read an AOS going is generally accompanied by a fairly unusual level of oil consumption. I'm losing about 1qt per 1000 mi, so thus far within spec. Thank you for the suggestions.

SergeSF

I am thinking that might be the cause. I just checked an inspection sheet that the mechanic did for a PDK service a month ago (wanted to do a full service early), they did mention that the tensioner shows a bit of a leak, but nothing drastic. My guess it could be losing tension and allowing the belt to squeak as it loosens.

ALEV8

Just checked the part cost. $436. Some disassembly required. Turn up the stereo......

SergeSF

Your $200 estimate was almost spot on.

https://www.fcpeuro.com/products/por...he-9a210221100 - $193
https://www.fcpeuro.com/products/por...na-9a110221200 - $17
https://www.fcpeuro.com/products/por...na-94810226100 - $26

Not hard to replace, just need a low-profile T50 to get it off.

jchapura

Yes, short drive should be OK. Maybe a couple miles tops (circle your house just in case)? Perhaps plan a morning and an upcoming cooler day. And keep off the A/C to minimize heat load. (Hopefully you can induce the problem in the driveway before the test drive.)
I understand your oil consumption may be in spec but that seems a bit high to me. My own data point is about 0.5-1.0 quart per 4000-5000 miles.

SergeSF

I'll check the vacuum to determine if the AOS is not doing well in that case. From everything I've seen the range is fairly wide between owners. Some consume more and others much less. The Porsche tech specs list 1.6 quarts per 622 miles (which is a ton, IMO).

So I took off the serpentine belt to spin each pulley individually. The first thing I noticed is that the tensioner did not return back to its original position after releasing. Since it's a hydraulic tensioner, I can't imagine it would be valved to stay in the position you leave it in. Since it is visibly leaking, I think it's safe to say that it's shot.

All the rest of the components spin freely, smoothly and without noise (although the A/C has a bit of resistance, which I will attribute to the clutch being partially engaged). The only exception is the alternator. Spinning it counter-clockwise results in a high pitched squeak at any speed. Clockwise it's quiet, which would make sense since it's supposed to spin clockwise (along with the crank, water pump, and A/C). The graphite brushes are most likely just squeaking from going against the direction they have been "grooved" in by the rotor.

SergeSF

Replaced the hydraulic tensioner. Went for a drive, car warmed up, still have the squeak (not as pronounced as before). Wondering what it is now.

SergeSF

Got a chance to replace the idler pulley as well (finally got that damn bolt free). Still got the squeak. Seems to be present between 1400-1700 RPM and again only under load. Next step will be to drive around without the serp belt.

ccdoggy

I am going to go a little against the others and say it might be normal (or I also have the problem). I have a similar whistle/squeal at ~1500-2000 RPM if I have the accelerator at just about the point where it would barely accelerate. If I push more or let off it disappears. Had it into the dealer who cleaned up my intake and throttle body to no change, they test drove another 997.2 and same thing was present. No matter the gear for me it comes down to how open the throttle body is (my only uneducated guess). It is slightly annoying but not dragging on my mind.

Thus, my question to you, does the noise go away if you press down on the accelerator? not a whole lot but maybe 1/4 inch?

SergeSF

My concern is that this was not present at all for the first 3000mi that I had the car. And it's quite loud, too. It does go away if I press on the gas. If I run through the rev range from a dead stop you won't hear it either (for long, at least).