Whistling noise from under the hood

Hi Everyone,

New to the forums.

The issue I'm having is with a whistling noise after changing the IAC valve.

Previous to the IAC valve change the noise was on and off.

Now its constant.

I went to the mechanic today, and its a first timer for them, they narrowed it down to the engine gaskets.

The intake air was blowing opposite.

I checked online and this maybe the problem, but I just wanted to confirm with you guys if you experienced the same.

I thought it was definetely vacuum tube plastic/rubber pipe broken.

Seems it is a much more expensive fix. 300 dollars and a whole entire day's of work apparently.

Any thoughts are appreciated!

Hi Everyone,

New to the forums.

The issue I'm having is with a whistling noise after changing the IAC valve.

Previous to the IAC valve change the noise was on and off.

Now its constant.

I went to the mechanic today, and its a first timer for them, they narrowed it down to the engine gaskets.

The intake air was blowing opposite.

I checked online and this maybe the problem, but I just wanted to confirm with you guys if you experienced the same.

I thought it was definetely vacuum tube plastic/rubber pipe broken.

Seems it is a much more expensive fix. 300 dollars and a whole entire day's of work apparently.

Any thoughts are appreciated! sounds to me that theres a vaccum leak some where since you changed iac i would look around there for a hose being off. dose it do it just setting there or do you have to be going down road? and dose motor idle smooth?

sounds to me that theres a vaccum leak some where since you changed iac i would look around there for a hose being off. dose it do it just setting there or do you have to be going down road? and dose motor idle smooth?

Previously the motor did not idle smoothly. The RPM would go below 500, and would randomly shut off.

The whistling noise would come and go, when it came reving the engine solved it temporarily.

And when I turn AC or heat on, the Rpm would jump up, and stay up until I shifted gears.

After changing the IAC, the idle seemed to be fixed, it would stay normal at around 800 Rpm.

But now the whistling noise is constant, it only dissapears while I'm on the gas peddle.

The mechanic disconnected one of the rubber hoses leading from the air intake, and the whistling stopped.

He said I could drive I come back tomorrow to get the gaskets replaced. But right when I drove out the engine shut off a few times, so he had to connect it back, but then the very loud whistling came back again.

Apparently 3 possible things need to be replaced:

intake (upper and lower) gasket
Throttle body gasket.

Your right about the vacuum hoses.

While I changed the IAC valve, the vacuum plastic tube broke, but I replaced it. I checked all the other vacuum tubes they all seem to be fine.

The whistling seems to be coming from the air intake compartment. The air intake was checked for any cracks, that was fine as well, seems its coming from the inside from the throttle body.

I'm guessing this is where the gaskets need to be changed.

So apparently, I have to pay around 300 dollars to change those parts which did not fix the issue.

This is very suspicious to me. The mechanic said it would take the entire day to replace, yet it took him about an hour it seems he forgot what he said the day before.

I don't get what the gaskets would do since disconnected one of the rubber hoses from the air intake throttle body fixed the whistling noise.

So apparently, I have to pay around 300 dollars to change those parts which did not fix the issue.

This is very suspicious to me. The mechanic said it would take the entire day to replace, yet it took him about an hour it seems he forgot what he said the day before.

I don't get what the gaskets would do since disconnected one of the rubber hoses from the air intake throttle body fixed the whistling noise.

Replacing the UIM and LIM gaskets is about a 1-2 hr job. Gaskets are about $25 piece ($50 total). It's literally as easy as unbolting the 6 UIM gaskets, disconnecting the EGR, unplugging the IAC, disconnecting the throttle body linkage, and the misc vacuum lines. Once that's off, the LIM is even easier. Pull off the fuel rail and injectors and undo 8 bolts iirc.

I have seen a PCV valve cause a noise like that.