Funny whining sound at 1800rpm

[monmendoza]

Good afternoon,

This is my first post here and probably in desperation. Im from the
Philippines and the Toyota 4runner was never sold here. I decided
to buy an imported 1997 4runner Limited for the Mrs..

But since I bought it, it is producing this annoying whining sound at 1,800
rpm. I have ask for advice from mechanics and have opened the whole
dashboard. so far none has been able to help. I hope that somebody here
has experienced the same problem. As I am almost ready to regret buying a 4
runner. Many thanks in advance for the advice and help.

Although non-critical (my 4runner has no other problem) it produces a
whining sound when moving and at an RPM of about 1800. There is
no sound higher or lower than approx. 1,800 rpm. If you step on the
brakes even very slightly the sound disappear.

When in park mode there is also no sound even in 1,800rpm range.

Here is a link to a youtube video where I recorded the sound.


YouTube - Funny Noise in 4runner

Thank you very much.

 

[monmendoza]

anybody?

 

[brian2sun]

I'm trying to tell whether the sound is related to the brakes/vacuum booster or the motor. Not a normal thing I've seen before. I am going to guess that it doesn't have anything to do with the brakes, but rather when you lift your foot off the gas to push the brakes, you reduce the load on the motor the sound goes away.

How about when you're going downhill and doing 1800 rpms (with little to no load on the motor)?

What I'm getting at is it sounds like the problem occurs at 1800 rpms, but only when there is load on the engine and that points to an engine issue. Maybe you have a pulley about to sieze up??

 

[monmendoza]

after more searching today using a microphone, we were
able to determine that the sound definitely comes from
inside the cabin, not from the engine hood. Tomorrow
we will check the brake booster assembly.