Elephant in my car? Weird noise help!

Post by **FlyingVolvo** » 14 Jun 2010, 20:51

Well I just started noticing a very peculiar noise coming from my car. For lack of better description, it sounds like an elephant in its death throes...

Just listen:

Seems to be coming from the exhaust area. Definitely not power steering, and I check the serpentine and timing belts to look for any evidence of rubbing but all looked normal.

I'm perplexed. Coincidentally my check engine light illuminated on the freeway, but nothing seemed out of the ordinary so I went on my way. Got my scanner out and it says that the CEL is off.

I did hear beginnings of the noise way before the CEl though.

Any ideas?

Edit: A comment on the video said turbo bearing? Googling some more I also saw someone who said his O2 sensor was loose making a squealing noise similar to this.

Post by **jblackburn** » 14 Jun 2010, 23:14

Are you sure you didn't hit a cat?

That sounds EXACTLY like our cat howling outside doors in the middle of the night.

It sounds to me like it might be a turbo bearing...that it comes and goes like that would almost suggest some sort of bearing noise, if you've ever spun a bad one.

Take off your IC pipe and try to shake the blades of the turbo back and forth and check it for play.

If that's not it, then I really have no idea. That's the strangest noise I've ever heard a car make.

Post by **FlyingVolvo** » 15 Jun 2010, 07:16

Yeah, it's got me stumped. I've used the turbo at certain points during the day with no issue. No strange sounds when producing boost.

I'll check to see if I got a cat stuck in the timing belt or something!

Post by **jblackburn** » 15 Jun 2010, 07:32

Actually, another possibility for you (I remember your overheating post from last week).

When the bearings/seals go bad in a water pump, they can make kind of a chirping/screeching noise like that. I have only ever heard them make a grating noise, but if you can't find anything wrong with the turbo blades, that could be where its coming from.

It wouldn't cause a CEL though, whereas a turbo binding up might throw off the airflow mix.

Post by **FlyingVolvo** » 15 Jun 2010, 07:35

Oh... that would be bad! Good suggestion though. I might see if I can take it to a local mechanic and ask for a quick "what do you think this sound is" deal.

I'll report back after checking the turbo. Meanwhile... any more suggestions would be great.

Post by **FlyingVolvo** » 15 Jun 2010, 14:42

So of course, today I don't hear a peep out of it. Showed my video to a local mechanic who said it sounded like a turbo bearing, especially since the noise seemed to come from the exhaust area, but that it would be unusual for there to be something wrong in the turbo while only hearing it at idle. Revving it up makes the noise go away (when it's actually there) and there is no audible noise when boosting on the freeway.

I pulled the IC hose only to find you can't see the propeller blades through that. I haven't had the time/energy to pull out the air intake hose again, especially after the PITA it was for the PCV job.

Post by **jblackburn** » 15 Jun 2010, 15:00

Whoops, yeah...that one...I didn't mean to say intercooler hose.

A bearing, wherever it may be, in early stages of failure may only a noise intermittently, and can be hard to track down as it is sometimes temperate or speed-specific.

That's a general rule of trying to diagnose something, as soon as you try to ask someone else, it will act perfectly fine. Everything of mine does the exact same thing. I've been trying to get a video of something weird my car is doing, and as soon as I pull out my iPod to take a video, it stops doing it, or hasn't in the past 2 days I've had it ready.

Post by **FlyingVolvo** » 15 Jun 2010, 15:08

Well since there is nothing I can even do up here, I think I'll go ahead with my trip home, just taking it nice and easy and listening for anything of the ordinary.

So far from I've noticed, and I'll need to pay attention more to confirm, that this noise only occurs when the car is warmed up. I don't recall ever turning the car on cold and hearing it. Not 100% on this one though.

Also, I was able to pull the code finally, and as I suspected it's the same Cat Converter code. I don't get it. I've gotten this code several times BEFORE and a couple times after I had a CA Smog Check which showed the CatCon was not only working, but performing very well. And this is CA we're talking about! This code went away for about 1500 miles and now it's back. My mileage is still normal.

Is there a connection for the converter which might be loose? I've also heard that the rear O2 sensor can cause this?