Whistling sound

[Mike F]

A few runs after my VOD job, the car began to make an odd whistling sound. It's one of those noises that seems to come from "everywhere" and I can't really pinpoint the source. It changes with acceleration, and my first thought was a vacuum leak somewhere. As part of the VOD job I replaced all of the vacuum lines with silicone ones, so I thought that maybe one had wiggled loose. I have checked every one that I can access and haven't found the culprit yet. I have checked that the ISM pipe (of agony) is seated properly by checking for stray light through the meter flap with the garage dark, and it seems to be sealed (as far as I can tell anyway). My worry is that it's one of the fittings on the vacuum switch in the y-pipe, but I made sure those were nice and tight before I reassembled everything. I shot a quick video of it, and it's at the link below:

http://www.youtube.com/watch?v=lf5Io77cqlI

Any thoughts? Suspect that it may not even be a vacuum leak? My next thought would be a bearing on one of the pulleys or tensioner. I was going to try removing the A/C belt to take that out of the equation but I thought I'd float it out here first.

[Patrick C]

I had a similar noise from my W pipe at the front of the intake. Tightening those bolts down a little more eliminated the problem.

[DMCMW Dave]

A few runs after my VOD job, the car began to make an odd whistling sound. It's one of those noises that seems to come from "everywhere" and I can't really pinpoint the source. It changes with acceleration, and my first thought was a vacuum leak somewhere.
Any thoughts? Suspect that it may not even be a vacuum leak? My next thought would be a bearing on one of the pulleys or tensioner. I was going to try removing the A/C belt to take that out of the equation but I thought I'd float it out here first.

Usually the paper gaskets at the W-pipe at the front of the engine. They should be new, and should use sealant.

[Jonathan]

I would have guessed it was an air moving related noise until seeing the last second of the video and the squeal stopping exactly as the A/C belt stopped. Try the A/C belt removal idea as you said especially since its easy.

[DMC5180]

I would have guessed it was an air moving related noise until seeing the last second of the video and the squeal stopping exactly as the A/C belt stopped. Try the A/C belt removal idea as you said especially since its easy.

What a coincidence, the noise stopped when engine stopped rotating too! Replace the engine and see if that fixes it. :rolleyes1:

[Mike F]

Thanks for the quick responses! Pulled the W-pipe, cleaned the surfaces again, and reassembled. Used gasket sealant this time; I hadn't before. I replaced the gaskets just a few days ago, so they're still pretty new (only had the engine run on them a few times). Hopefully they are still new enough to reuse. I'm going to wait a while for the sealant to set and will fire it up.

[DMC5180]

Thanks for the quick responses! Pulled the W-pipe, cleaned the surfaces again, and reassembled. Used gasket sealant this time; I hadn't before. I replaced the gaskets just a few days ago, so they're still pretty new (only had the engine run on them a few times). Hopefully they are still new enough to reuse. I'm going to wait a while for the sealant to set and will fire it up.
:thumbup:

[DMCMW Dave]

The strangest one of these that I'd seen was a noisy brand-x water valve. Remember that vacuum is only sent to that valve with the A/C set to Max.

If you set the A/C to anything but MAX the noise went away.

[Mike F]

Ok, I let it set overnight. Started it up this morning and let it run for a while; no noise! I waited a couple of hours and went for a drive, and it was still quiet. Looks like that did the trick! One of the things I originally suspected was the W-pipe, but after retightening the bolts didn't fix it I moved on. I likely wouldn't have revisited it anytime soon had I not received that advice! Thanks for the help!


The strangest one of these that I'd seen was a noisy brand-x water valve. Remember that vacuum is only sent to that valve with the A/C set to Max.

If you set the A/C to anything but MAX the noise went away.

That is odd. I'll bet it was fun chasing that one down.