Updated squealing noise

[Arty]

Ok, some may remember my post a bit over a month ago about a strange squealing noise emanating from my engine bay under heavy throttle. Well, I'm here to say that the noise is most certainly NOT coming from the engine. It's actually coming from the back right hand side of my car. It actually sounds almost electronic in its pitch. My wife, who knows little to nothing about anything mechanical, even said "That is too high pitched to be anything mechanized."

 

 

So I've now narrowed it down to two things-

1- Fuel pump

2- A strange hole in my exhaust.

 

 

I've run so many clutch tests to positive results that I can no longer believe it's the clutch. I WILL have it checked out in about 9 days, but until then, I would just like some other ideas.

 

Like I said, the sound is ABSOLUTELY NOT coming from the engine, transmission, or even the diff. for that matter. It's coming from the back right hand corner of my car.

[Arty]

I'd also like to say that I thought fuel pump at first because of the sound's location, and the exhaust idea came after much Googling of the symptoms. I assure everyone that this is not a blindly concocted notion. I'm just unsure how likely one is over the other.

[allwheeldad]

My 99 Legacy GT has had a high pitched whine at wide open throttle since I've owned it. It is exhaust related, but since I have never thrown a CEL code over it, I just never bothered with doing anything about it.

[Arty]

I just randomly found this video made by one of our own users. It is pretty much the EXACT SAME noise, only mine isn't quite as intense. And like I said, it definitely is not coming from the engine bay whatsoever-

 

[idosubaru]

it might help to know what car, year, model we're talking about.

 

some other really important information: is it completely constant and never varies? if it varies - how? with engine speed, at idle, acceleration, deceleration, turning, etc.

 

fuel pump is centrally located and the exhaust is not on the right side either so that rules both of those out.

 

right/left is determined as if you're sitting in the car so "left" means drivers side, is that how you were using it? sometimes d/s, p/s or drivers side, passengers side is more clear.

 

the rear right houses some evap stuff...but you haven't mentioned year/vehicle and that stuff can be up front too. do you have a charcoal canister up front?

 

ever have a check engine light?

 

need some more info but my first thought is the heat shield.

[Arty]

it might help to know what car, year, model we're talking about.

 

some other really important information: is it completely constant and never varies? if it varies - how? with engine speed, at idle, acceleration, deceleration, turning, etc.

 

fuel pump is centrally located and the exhaust is not on the right side either so that rules both of those out.

 

right/left is determined as if you're sitting in the car so "left" means drivers side, is that how you were using it? sometimes d/s, p/s or drivers side, passengers side is more clear.

 

the rear right houses some evap stuff...but you haven't mentioned year/vehicle and that stuff can be up front too. do you have a charcoal canister up front?

 

ever have a check engine light?

 

need some more info but my first thought is the heat shield.

 

 

It's a '95 Legacy Outback. It DOES have a check engine light, but it's throwing an o2 sensor code. The sound is very rare, as it only occurs under very heavy throttle... I don't like ragging it out like that. In terms of location, it's the right rear if you're sitting in the driver's seat facing forward.

 

I'm starting to suspect a heat shield as well. Is there any possible way that could be what's causing the CEL to be on?

[Rooster2]

No, the heat shield can not cause a CEL to come on. The heat shield has nothing to do with the operation of the car. It's sole purpose is to prevent a grass fire should you ever pull in and park in an area with high grass and weeds. The heat shields prevent the weeds from coming into contact with hot exhaust pipe, which could cause a fire.

[Arty]

No, the heat shield can not cause a CEL to come on. The heat shield has nothing to do with the operation of the car. It's sole purpose is to prevent a grass fire should you ever pull in and park in an area with high grass and weeds. The heat shields prevent the weeds from coming into contact with hot exhaust pipe, which could cause a fire.

 

Alright, so I guess I'll change the o2 sensor anyway. Rats. I was hoping it was related.

[idosubaru]

The exhaust is not routed to the right rear unless maybe you have a postal right hand drive vehicle or something different. Exhaust is left rear.

 

There is a "chance" the noise and O2 code are related....if the exhaust has a leak...maybe this is a "hissing" sound, then that can trip an O2 sensor code.

 

You mention O2 code - there are various O2 codes. Some (like the P0420 i believe) often will not be fixed just by replacing it.

 

If you tell us which O2 sensor code you have we can help guide how to fix that (which may or may not mean replacing the sensor depending which code and which sensor it is), and if it's related to the noise or not. There are some very competent folks on here but without seeing, hearing, touching, driving, inspecting the car it really helps to have important information on hand. A CEL is always good to know and we would want to see the actual code number, not just what some guy at an Autoparts store tells you what it is.

[johnceggleston]

if the exhaust has a leak under heavy acceleration i would check the donut gasket just to the rear of the trans where the cat meets the mid-pipe. it is usually a spring loaded joint and heavy acceleration can be more pressure than the seal can handle.

 

but , that is not right rear, it is very much center center of the car.