Please help diagnose this problem

[S4audi15]

I thought it was the belt but put different belt and still made noise. I thought it was idler pulley and I changed that but still noise. Maybe the tensioner. Here's a video.

[S4audi15]

If video doesn't work here it is on my youtube.
http://youtu.be/y1qcNUCqwW4


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[S4audi15]

Anybody have an ideas?? Would love to hear any feedback before I go replace the tensioner that might not fix it and waste more money. The high pitch whistle sound can be heard when revving the car quickly in neutral. I also have a P0235 code supercharger boost sensor a circuit that goes on and off all the time. This code has been coming on and off way before I started hearing this noise, not sure if it's related.


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[SportVier]

Loose belt makes basic sense to me, both in terms of the sound and boost error. Tensioner seems like a logical next step.

[Jflow23]

Anybody have an ideas?? Would love to hear any feedback before I go replace the tensioner that might not fix it and waste more money. The high pitch whistle sound can be heard when revving the car quickly in neutral. I also have a P0235 code supercharger boost sensor a circuit that goes on and off all the time. This code has been coming on and off way before I started hearing this noise, not sure if it's related.


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I'm thinking the code and the issue are related...possibly boost/vacuum leak. What mods do you have? What maintenance was done when the problem first came to light?

At first I thought the whistle was belt squeal, but the way it changes pitch makes it seem more like a whistle from escaping air via a small hole. The change in pitch when you lift throttle is also an indicator to me. Can you shoot another video revving in neutral? When you do it, move the camera around the supercharger as well...don't just focus on the belt area. Make sure you move the camera around slowly while you film...may help you isolate location when the noise occurs.

There are a couple videos on youtube about belt chirp v squeal and the causes. You can troubleshoot most with water and a spray bottle.

If you think it is S/C belt related...you can remove that belt and rev the car in neutral, if the sound persists...S/C belt is not the culprit. This will also let you begin diagnosing the serpentine system in isolation.

[autobahnaudi]

I would say check for a vacum leak also, makes the most sense given the noise it's making and he boost codes. Also like they said above rev while you look around and listen under the hood, you need to isolate more where the sound is coming from.

[S4audi15]

I'm thinking the code and the issue are related...possibly boost/vacuum leak. What mods do you have? What maintenance was done when the problem first came to light?

At first I thought the whistle was belt squeal, but the way it changes pitch makes it seem more like a whistle from escaping air via a small hole. The change in pitch when you lift throttle is also an indicator to me. Can you shoot another video revving in neutral? When you do it, move the camera around the supercharger as well...don't just focus on the belt area. Make sure you move the camera around slowly while you film...may help you isolate location when the noise occurs.

There are a couple videos on youtube about belt chirp v squeal and the causes. You can troubleshoot most with water and a spray bottle.

If you think it is S/C belt related...you can remove that belt and rev the car in neutral, if the sound persists...S/C belt is not the culprit. This will also let you begin diagnosing the serpentine system in isolation.

I have a tune, pulley, and intake. The thing is the check engine light has been coming on and off ever since I put my roc euro intake on.. The light came on way before the car started making this noise.. My shop said it was the idler pulley gone bad so I replaced it and while replacing we revved with belt off and still made noise.. After I replaced idler pulley it actually seemed to temporarily fix the noise but then few days later the noise came back. I will take a video tomorrow revving it in neutral.


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[S4audi15]

Loose belt makes basic sense to me, both in terms of the sound and boost error. Tensioner seems like a logical next step.

Ya the shop I got my idler pulley installed at said if noise persists it's prob the tensioner.. I just don't wanna replace that and there's still noise. Already wasted $150 on replacing idler for no reason so I'm prob bringing to another shop later this week for another opinion


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[Jflow23]

I have a tune, pulley, and intake. The thing is the check engine light has been coming on and off ever since I put my roc euro intake on.. The light came on way before the car started making this noise.. My shop said it was the idler pulley gone bad so I replaced it and while replacing we revved with belt off and still made noise.. After I replaced idler pulley it actually seemed to temporarily fix the noise but then few days later the noise came back. I will take a video tomorrow revving it in neutral.


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If it made the sound without the belt installed, then the belt and components are not the problem. A new tensioner is unlikely to resolve the issue.

[jsh139]

I have a tune, pulley, and intake. The thing is the check engine light has been coming on and off ever since I put my roc euro intake on.. The light came on way before the car started making this noise.. My shop said it was the idler pulley gone bad so I replaced it and while replacing we revved with belt off and still made noise.. After I replaced idler pulley it actually seemed to temporarily fix the noise but then few days later the noise came back. I will take a video tomorrow revving it in neutral.


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You have the vacuum hose installed on the back of the intake, right? Back towards the throttle body. Also check the breather hose.

[S4audi15]

If it made the sound without the belt installed, then the belt and components are not the problem. A new tensioner is unlikely to resolve the issue.

I'm sorry there was no noise when the belt was off the car that's why I'm thinking maybe tensioner


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[S4audi15]

I'm thinking the code and the issue are related...possibly boost/vacuum leak. What mods do you have? What maintenance was done when the problem first came to light?

At first I thought the whistle was belt squeal, but the way it changes pitch makes it seem more like a whistle from escaping air via a small hole. The change in pitch when you lift throttle is also an indicator to me. Can you shoot another video revving in neutral? When you do it, move the camera around the supercharger as well...don't just focus on the belt area. Make sure you move the camera around slowly while you film...may help you isolate location when the noise occurs.

There are a couple videos on youtube about belt chirp v squeal and the causes. You can troubleshoot most with water and a spray bottle.

If you think it is S/C belt related...you can remove that belt and rev the car in neutral, if the sound persists...S/C belt is not the culprit. This will also let you begin diagnosing the serpentine system in isolation.

https://youtu.be/gBFvPRcELNo

https://youtu.be/O6pg3bmBuNI


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[Jflow23]

Sounds like belt slippage...what belt are you running? I assume a 7pk1270...whatever brand came with your pulley? Have you tried a different belt? If you hold the gas in neutral, the car will only rev to 4k...if you do that, is the sound persistent?

[S4audi15]

Sounds like belt slippage...what belt are you running? I assume a 7pk1270...whatever brand came with your pulley? Have you tried a different belt? If you hold the gas in neutral, the car will only rev to 4k...if you do that, is the sound persistent?

Yes 7pk1270 I haven't tried a different belt yet was planning on getting same (new belt) and new tensioner and seeing if noise stops. Do u think I should get a smaller belt if they even make it? And when car is in neutral it makes the noise when I rev it up quick to 4K rpm (when I make peak boost I guess) the noise is there on most revs but sometimes goes away temporarily.. Noise starts after 3500 rpm it's not really there if you just hold it at a steady 3500 but I could try that again tomorrow. Mechanic also said that my water pump looked bent out of shape..


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[Sudz]

If the tensioner is weak it will delay tightening the belt, momentary belt squeak. That's what I hear in the video.
The belt also wears each time this happens, so it gets worse.

[S4audi15]

If the tensioner is weak it will delay tightening the belt, momentary belt squeak. That's what I hear in the video.
The belt also wears each time this happens, so it gets worse.

Thank you I'm hoping this is right and fixes the issue. I have an aftermarket pulley but not an aftermarket tensioner so I feel that the tensioner being weak/bad is a good possibility.


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[Jflow23]

Recommend doing the belt with the tensioner...worn belts stretch and also contribute to the issue. You could honestly do the job yourself in about 20 minutes if you have the triple square bit.

I've removed mine a few times chasing down a belt issue of my own. All you need to DIY it is a jack, jack stand, screwdriver for belly pan Dzus fittings, 16mm wrench to rotate the tensioner, and the triple square bit to remove the bolt. There is sufficient room to operate...it's nothing like changing the supercharger roller.

[S4audi15]

Recommend doing the belt with the tensioner...worn belts stretch and also contribute to the issue. You could honestly do the job yourself in about 20 minutes if you have the triple square bit.

I've removed mine a few times chasing down a belt issue of my own. All you need to DIY it is a jack, jack stand, screwdriver for belly pan Dzus fittings, 16mm wrench to rotate the tensioner, and the triple square bit to remove the bolt. There is sufficient room to operate...it's nothing like changing the supercharger roller.

Thanks for all the info! I ordered a new belt with the tensioner I'm gettin it done at my shop tomorrow good to know that it shouldn't take them more than a half hour or so.. Fingers crossed that this fixes the issue..


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[S4audi15]

For anyone that may encounter the same problem I did in the future my issue was resolved. I put a new tensioner and a new belt and belt slippage sound is gone. My shop installed tensioner but forgot to put the new belt on at first when I went to rev car it still made the noise. We realized new belt wasn't put on so we put it on and noise went away. I wonder if I put just a new belt in and left my old tensioner if the noise would have went away. Also, my Shop said noise might come back if belt starts to wear and recommended getting a smaller belt. Not sure if anyone has experimented with a smaller belt.


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