Topic: new noises - not indigestion!!

[Treeman]

I have recently had some new noises from my engine - and no, I have not been feeding it Mexican!  I can't find anything like these in searching the forums and, although I can see no effect on the engine's operation at the moment, I worry about new noises.

The first happened during my last autocross.  I posted that I did not go off course but the results show I did.  That's because I didn't count the run as I went deliberately off course.  I was going WOT in 2nd, pulling up from a lower speed corner (on my last run I tried 1st here but it slowed me down) when I head the sudden onset of a sound exactly like when you blow up a balloon and stretch the mouth of the balloon tight while letting air out.  Not a flatulent sound .... [pause for GJ comment] ... but the high pitched noise.  I popped the hood and looked at the usual suspects of turbo hose connections but all was good.  Never lost boost and the only impact on the engine was me taking my foot of the gas.  Someone suggested the wastegate.  I have been hard on the gas before and so was doubtful, but since I could find nothing wrong I jumped right back into things and made several more runs.  Heard the sound again at the same place, kept going, and made fast times.  OK, perhaps wastegate but don't know why I never heard it before .... anyone else heard their wastegate like this?  Also, I thought a wastegate dumped into the exhaust so why would I hear it from under the hood?

The second noise started the next morning when I started the car.  I don't know quite how to describe the noise other than a whirring whine - kinda like a vacuum cleaner sound but more muted and polished.  I get it right when I start the car and it whines down in pitch as the engine slowly drops to idle and goes away.  If I rev the engine up to cold idle speed when it is warm the sound does not come back.  This morning, I had a little extra time and popped the hood to try and locate the noise.  Before it went away, it sounded like (without using a stethoscope) it was coming from right around the turbo.  Which is why I also mention the autocross noise.  Again, the car seems to run fine but new noises worry me.

Could it be a wastegate valve problem?  Could it be a turbo issue that goes away as soon as it is warm (thinking either oil not getting where it is supposed to be or heat expansion closing up a new gap in something?  Could I be a hypochondriac?

BTW, this all started only a couple of days after they installed the new GMPP sensor in my car.

[kennysabarese]

Sounds like intake elbow or turbo compressor elbow. Mine was loose but you couldn't tell from visual inspection...

[Treeman]

I wiggled them and they seemed tight.  But they still could be loose?

[DeepBlueGXP]

I had those noise on Chuckdoc's car when we popped off the hose on the turbo intake elbow.  I had just taken my prilosec so I know it wasn't from eating mexican

[TomatoSoup]

I wiggled them and they seemed tight.  But they still could be loose?

Could be.... I'd put DDM t-clamps on mine and though they seemed tight, at one point one on the front elbow (driver side) "ballooned" off.  Undid clamp and replaced-retightened (harder) and has been OK since.

I do hear my wastegate though when I let off the gas and it sounds like a short chirpy sound similar to what you described.

[DeepBlueGXP]

That part is normal. 

[Treeman]

Agree - that's the blow-off valve.

[elff]

The initial sound you described is similar to when I lost a clamp on a Dyno day.
Do you still get full boost all the time?

I have a Dejon intake, and everytime I start the car.  In my case, it's definitely the car sucking in extra air until it hits it's normal idle speed and temp.  I wonder if you have a leak in the intake system

As such,
I would also recommend that you check your clamps on all the pipes

[Critterman]

Do you have the A/C on?
If not while it is whirling, move the steering back and forth, does it change pitch?

Can't help you with the other problem,

[Treeman]

No A/C, will recheck the clamps (have full boost), will try the steering wheel.

Thanks!

[Gentleman Jack]

anyone else heard their wastegate like this?  Also, I thought a wastegate dumped into the exhaust so why would I hear it from under the hood?

along with the other advice, I believe this is different?

I think the wastegate actually dumps the air back in front of the turbo, in the air intake line, as opposed to the exhaust line, which would make it sound like it is coming from under the hood and the passenger side specifically.

GJ

[Arabas]

Treeman, i believe that if you could capture a video with the sound u have at start up, people here would be more able to check

[Treeman]

Tightened up the t-clamp at the turbo out hose connection last night.  Took it out and found a place where I could try and recreate my autocross acceleration run - no noise so hopefully that problem solved.

But, startup noise still there this morning.  Moving the steering wheel had no effect.  I will try and do cell phone video (best I can do) when I have some time in the morning - may be this weekend - and post.

Edit:  Gosh, I'm getting old.  Of course, my digital camera can do videos.  Doh!!!

[Critterman]

bummer, because if that was it, it was an easy fix.

[DeepBlueGXP]

Have you replaced you IC pipes before and potentially a clamp is loose?

[Treeman]

Have not replaced the pipes.  Replaced the hose clamps with DDMs t-bolts on the driver side. 

[MGar]

A loud noise, similar to a vacuum is typical on cold start when you have an intake.  However, since you don't appear to have an intake, I would inspect all clamps and connections that go from the turbo to the airbox.  If the sound seemed to be coming from the turbo, it may well have been the clamp that connects the intake on the turbo.

If all of your above problems keep happening, and it is the hose/clamp I think it is, one would normally suspect a motor mount failure causing these problems to re-occur.

[rich71]

i hear a muted hairdryer sound on the 1st cold startup of the day. maybe 15 seconds-ish - i assumed it was a evap pump for emissions or something - my saturn sw2 wagon makes the same sound and that for sure is a "smog" device for fuel evap.

[Treeman]

A loud noise, similar to a vacuum is typical on cold start when you have an intake.  However, since you don't appear to have an intake, I would inspect all clamps and connections that go from the turbo to the airbox.  If the sound seemed to be coming from the turbo, it may well have been the clamp that connects the intake on the turbo.

If all of your above problems keep happening, and it is the hose/clamp I think it is, one would normally suspect a motor mount failure causing these problems to re-occur.

Interesting thought.  I did not look on that side of the turbo piping since it is negative pressure.  But will check and see.

I would think if I had motor mount failure I would get a fair bit of vibration.

[Treeman]

i hear a muted hairdryer sound on the 1st cold startup of the day. maybe 15 seconds-ish - i assumed it was a evap pump for emissions or something - my saturn sw2 wagon makes the same sound and that for sure is a "smog" device for fuel evap.

That sounds about the same.  Interesting though, that for me, it did not start for 12k miles and a year and a half.  Since things seem to run OK, it may be nothing - or something that hasn't grown serious yet.  Which is why I'm checking.

Will post the vid this weekend - please check back and let me know if it sounds like your car.

Thanks!

[MGar]

I would think if I had motor mount failure I would get a fair bit of vibration.

It's also the first time you've had the problem.  If it continues to re-occur, the mount may be beginning to fail, allowing a bit more twist on the turbo, while the airbox & intercooler are secured to the frame.

[Treeman]

Will post vid tomorrow but this morning, used a breaker bar as a stethoscope and it is definitely coming from the front part of the turbo housing  - and not where the hoses connect to it.  It is also truly gone once the idle speed drops.  So I am guessing the air intake impeller (or whatever it is properly called) is not getting oil right at startup.  Not good for long-term wear I guess.  As I am typing this at work, I just recalled that I also had the oil changed when the dealer replaced the GMPP sensor a couple of weeks ago so I will check the oil level when I get back to the car.  If it is not that, I am not sure what to think.  If it was crud stirred up in an oil change, I would think it would stick around and not go away as soon as idle speed dropped.

[Treeman]

OK, here is the vid.  My only comment is that the microphone does not make it seem as loud as it is - it seems to be tuned more to pick up the mechanical clatter than the whirring noise.  If you mentally reverse the volumes it is about right.

Thoughts?

[youtube]http://www.youtube.com/watch?v=YDqT6KO-LdU[/youtube]

[Jackknife]

Sounds like impeller blades hitting the casing.  Either that or a dry bearing.  Heat might cause expansion--more clearance...less noise.

[Arabas]

Sounds like impeller blades hitting the casing.

that would also be my first guess. i think u should have your turbo checked.
funny things is when i first heard the video, my mind went to those old cars.
remember how some times  old cars start whining at start up and it s that belt in the front of the engine connecting some wheels, that is loose. sorry to not post it with the right words, but i don t know how it is called...