02 Es Noise On Acceleration

[branshew]

When I accelerate from a low speed or stopped position, I hear a noise inside the cabin. Somewhat hard to describe the sound, but for a while I thought that I had an acorn or loose nut bouncing around inside an air plenum when I was accelerating. The noise is similar to a mix between a clicking/popping and fluid bubbling/sloshing inside a closed system. It is coming from behind the dash area.

I can duplicate the sound with the car in park or neutral and revving the engine, but it is slightly more pronounced when the car is driving under a load. The noise subsides once I get past 1500 RPMs. Here's the strange part - the noise can only be heard inside the cabin. I had someone inside revving the gas and I was listening under the hood and couldn't hear anything. It happens withthe HVAC on and off (w/ & w/o the A/C).

I am ususlly pretty good at diagnosing problems, but this one has me stumped. The only thinking that I can think of is that some air is trapped inside my heater core and that the coolant flow through the core is making some noise, but that may be a stretch. TB & WP were changed out about 2 months ago and the noise has surfaced since then, but I can't tie it directly to that.

Any thoughts?

[upabove8]

recently bought a 2000 ES300. I hear the exact same noise. I thought it was ait leaking in from the window, but like you said i hear it coming from behind the dash. Sorry but i dont have a solid idea. =/

[branshew]

I just realized that I forgot to post the solution on this one. I hate unresolved problem threads so I dug it out of the past to update.

Rcently did a full fluid change and under-hood inspection. I saw that the coolant was a little low before draining it. When I refilled with fresh coolant to the proper level, the noise went away.