I thought I had nipped the problem by lubricating the heater core pipe grommets going into the firewall. The buzz is back, it seems like something along the firewall is causing the buzz to propagate behind the driver side dash.

The noise disappears in Neutral
The noise is there in Drive with brakes applied
As soon as I release the brakes the noise dies downs , sometimes goes away

I'm running out of ideas

I'll buy a clue from anyone ?

 

Most likely its your heater/ac fan, take apart your glove box and screw the fan down it should solve your problem.

 

Can you tell what this looks like? Ive taken my glove box out in search of an irritating knocking noise from under the dash, but dont know what to look for (other than just trying to feel if anything is loose or displaced). This may not be related to the rattle im getting, because mine is constant and loud when driving, especially over bumps...

 

Does it happen with the a/c or heater of? and when you open the glove box and see the filter thats the fan box.

 

Hi Amul,

I think your noise could be caused by a mild resonance that happens when the engine is at a certain rpm. In Neutral, the engine rpm is different than in Drive. When you let go of the brakes, the engine rpm goes up a little, so the noise stops.

Although my car doesn't have this particular rattle, I can confirm a mild resonance in D at idle. I can feel it in the steering wheel while waiting at the light.

 

I can hear it coming from the engine compartment with my door open. The buzz I hear is not the fan or AC, both are off and I can still hear it. It also seems to change with idle in drive, and it changes in sound when the ABS pump is cycling.

 

omg i hear the same thing! lol, i naively thought it was just part of the car operation. if you find out what it is, please let us know. I have the same symptoms you are describing.

-Rafael

 

i had the same thing also, i have also heard its 100 percent normal.....its a buzz followed by a click when u brake.... probably has something to do with them too. i wouldnt worry about it......thats kinda like picking at the little things, these cars have all different types of operations and im pretty sure thats just one of them.

 

You are describing the buzzing from the ABS pump, which is normal. You will hear it when you start the car, and often after you apply the brakes for any length of time.

I think Amul is describing something else, more like a light rattle from a loose part.

 

That's correct. I'm well aware of the ABS pump noise. That's a whole different story. Lexus says it normal, but I feel it's a design problem. There is no excuse for it to be that loud, considering my other cars which have ABS do not make this sound.

LEXOOS will be helping me out this weekend installing new struts and mounts. We may spend some time trying to identify the source.

 

I can't thank Lexoos( Jake) enough for helping me out with the strut replacement, throttle body cleaning, and the "buzz kill" . I just came back from a 1hr road trip on the highway, and the car handles better than ever. It's much quieter over small bumps and cuts straight as an arrow. Prior to this I had the ball joints replaced and a re-aligment, but I must say the strut/mount replacement was well $$ and time spent .

BTW

On top of that, we were able to isolate the buzz for good.

The source that produced the buzzing sound in the dash was something that I would have easily overlooked . You would think a dash rattle should originate somewhere within the dash, or pipes going in/out of the firewall, or somewhere on the surface of the firewall?

It was a semi-rigid pipe in the open area near the exhaust manifold, below the master cylinder. The pipe was attached to the chassi with a metal clip which needed to be folded inwards a little more to create some force to hold against the chassi. We bent the clip a little and wrapped some electrical tape around the clip to cushion the pipe( prevent metal to metal contact).

IF someone has a dash buzz that get's louder when pressing the brake, in Drive, while idlilng, this would be the first place to look. I'm sure all our cars are built following SOP( standard operating procedures), thus common annoying problems like this will pop up on other peoples cars sooner or later.

I can send a pic to anyone who may have an interest.

 

You got it buddy, i'm happy for you as well

 

I'd like to post pics, but my file limit size is 100K?