93Jaffe

It's been far too long since I've logged onto Rennlist - life's been crazy for everyone I suspect. Anyways, I am hoping to tackle an issue that has been getting worse that I ignored while the car slept over the winter. On startup I am greeted with a high pitch squeal that dissipates completely once up to temp. (For those that did not follow along I had an issue with my tensioner pulley bolt backing out and snapping, likely the cause of this noise). I had purchased a replacement tensioner pulley, but unless the thread is reversed I believe the PO used red loctite on this bolt. I completely sheared the teeth off of the torx bolt so fingers crossed that's not the issue.

I was hoping someone might recognize this noise before I go spending money on tools to diagnose the noise. Right now I am leaning towards the water pump but the alternator has quite a bit of crusty, crunchy noises when spun by hand.

yelcab

That is clearly a pulley noise. I don't know how many miles are on your 997.2, but all belt pulleys on Porsche 996/997 should be changed at 60K miles, as well as the water pump. Don't worry which one, just change them all. It's called preventive maintenance which eliminates their failure.

93Jaffe

Well, this place is much more passive aggressive than the last time I visited. Guess a pandemic will do that. Believe it or not I do know the noise is coming from the pulleys already. I was hoping someone might recognize the exact sound from their past. I went ahead and ordered a stethoscope kit to pinpoint the noise - I assume its the water pump at this point even though it was replace ~25k miles ago.

Petza914

The .2 cars don't seem to eat water pumps in the same way the .1 cars do. If you had that replaced once already, I doubt it's that. Best thing to do would be to remove the belt and spin and wiggle the pulleys by hand. Find the offending one and replace it, or replace them all if you're so inclined.

93Jaffe

Thanks Petza, I will have to come back with an answer once I have time to mess around with the stethoscope.

campbesl

I was just experiencing a similar problem though not as pronounced. I bought the serpentine belt kit from Rock Auto (best price around) but didn't tear into things deep enough to replace the belt tensioner block. However, replacing all three pulleys and the belt was straight forward and solved the problem. From my experience I suggest that you just buy the pulleys and belt rather than the whole kit. Good luck with yours.

PierW

Not to get off-topic, but similar line of thought. I've recently noticed the briefest of "chirps" when I first start up and then another just as I shut down. Same thought... is this a pulley that is just starting to fail? I'm due to replace the serpentine...

4Driver4

I've never heard a noise like that from a water pump. My money's on the pulley.
(too passive/aggressive, not enough, or just right? LOL)

dgjks6

Backyard mechanic here. Lots of pulley and belt changes. A "chirp" is usually bad belt slipping. A "squeal" is usually a pulley.

I said usually. There is room for overlap. My 997.2 chirped on cold start in the winter. Car only had 30,000 miles. But belt was 8 years old. New belt with no pulley changes solved the problem.

PierW

Thanks DG...I had been planning on replacing the belt (looks fine, but since I don't know when it was done, don't want to take a chance). We'll see if that cures!

campbesl

You described the symptoms I was having though it was progressing from brief to not so brief.

93Jaffe

Update: I solved, or so I thought, the noise on startup. I replace the tensioner pulley after a long battle of removing, replacing the pulley and reinstalling the arm. It appears that someone had replaced this pulley before and had used red loctite...

But now a few rides after the replacement I am starting to have the same noise and issues arise. Any thoughts as to what might be causing this? I have two main thoughts currently;
A) The arm's bolt is too tight so the tensioner is not able to apply the correct pressure on the belt
B) the arm's bolt is too loose so the pulley does not operate perpendicular to the belt

I am not able to fit a wrench to tighten the arm's bolt but I had backed it off slightly after instal because I could not move the arm freely. Any advise would be great. Thanks again,

93Jaffe

Here is how the belt is sitting on the pulley. It appears to be misaligned with the crank pulley (?).

93Jaffe

And one last update;

I removed a washer between the arm and the block that I did not see on the below assembly. This further extended the pulley out of line with the others but seems to be doing the trick for now.

Should this washer be there? I reassembled the arm exactly how it was before.

chonniedotcom

When running, spray water on the belt using a spray bottle.. if the noise goes away for a bit, then new belt will do it... I had the same last year, changed the belt, has not come back since.